Story highlights The United States believes pro-Russian rebels shot down the Malaysia Air jetliner

American officials say Russia bears the blame for supplying rebels with missiles

A U.S. official said Russia 'will have a hard time explaining this away'

But it's unclear how Russia's Vladimir Putin will respond. Will he back down in Ukraine?

The United States predicts the shooting down of Malaysia Airlines Flight 17, likely by pro-Russian rebels, will fundamentally shift the relationship between Russia and the international community.

"It is a game-changer," one senior State Department official said.

While Washington has stopped short of blaming Russia, U.S. Ambassador to the United Nations Samantha Power said Friday the United States believes the jet carrying nearly 300 people was downed by a surface-to-air missile fired by pro-Russian rebels in eastern Ukraine.

Due to the sophistication of the Buk missile system believed to have been used, Power said it was "unlikely that the separatists could effectively operate the system without assistance from knowledgeable personnel."

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Photos: Photos: Reaction to MH17 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Families of crew members aboard Malaysia Airlines Flight 17 gather for a vigil Tuesday, July 22, in Kuala Lumpur, Malaysia. All 298 people aboard the passenger plane died when it was shot down Thursday, July 17, in a rebel-controlled part of eastern Ukraine. Hide Caption 1 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – A woman cries July 22 during a service near the crash site. Hide Caption 2 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – People in Melbourne gather to mourn the victims during a candlelight vigil at Federation Square on July 22. Hide Caption 3 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – In memory of two Newcastle United fans who died in the crash, two wreaths are placed on seats July 22 at the Forsyth Barr Stadium in Dunedin, New Zealand. The soccer fans were traveling to New Zealand to watch their team play in a preseason tournament. Hide Caption 4 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – A KLM employee reaches out into a sea of flowers July 22 at Schiphol Airport in Amsterdam, Netherlands. Hide Caption 5 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – A flower and stuffed animal sit near the crash site on Monday, July 21. Hide Caption 6 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – A woman in Kuala Lumpur attends a candlelight vigil on July 21. Hide Caption 7 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Ukrainian President Petro Poroshenko attends a flower-laying ceremony at the Dutch Embassy in Kiev, Ukraine, on July 21. Although the passengers came from all over the world, many of them were Dutch because the flight originated in Amsterdam. Hide Caption 8 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – A woman places a flower during a candlelight vigil in Kuala Lumpur on July 21. Hide Caption 9 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Mourners in Eynesbury, Australia, attend a memorial service Sunday, July 20, for a family of five killed in the disaster. Hide Caption 10 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Buddhist monks in the Malaysian capital light candles during a special prayer for the victims on July 20. Hide Caption 11 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Wildflowers lie on an engine from the crashed jet on Saturday, July 19. Hide Caption 12 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Friends of Nur Shazana Mohamed, a crew member aboard the flight, take part in a special remembrance prayer at a mosque in Putrajaya, Malaysia, on July 19. Hide Caption 13 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Dutch Prime Minister Mark Rutte signs a condolence register at the Ministry of Safety and Justice in The Hague, Netherlands, on Friday, July 18. "I want to see results in the form of unimpeded access and rapid recovery," Rutte said in a press briefing. "This is now priority number one." Hide Caption 14 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – People pray for the victims of Malaysia Airlines Flight 17 at a church outside Kuala Lumpur on July 18. Hide Caption 15 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – A woman in Berlin places a candle at a memorial on July 18. Hide Caption 16 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – People in Kiev gather to mourn the victims on July 18. Hide Caption 17 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Akmar Binti Mohd Noor, whose sister was aboard Flight 17, cries outside the family holding area at Kuala Lumpur International Airport on July 18. Hide Caption 18 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – A man prays at a memorial in front of the Dutch Embassy in Kiev on July 18. Hide Caption 19 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Dutch cyclists wear a black armband in honor of the crash victims during the 13th stage of the Tour de France on July 18. Hide Caption 20 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Dutch Justice Minister Ivo Opstelten observes a moment of silence after signing a condolence book in The Hague on July 18. Hide Caption 21 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Candlelight prayers honor the victims at a church outside Kuala Lumpur on July 18. Hide Caption 22 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Floral tributes adorn the entrance to Schiphol Airport in Amsterdam. Hide Caption 23 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – A Dutch flag flies at half-staff in The Hague on July 18. Hide Caption 24 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – People place flowers in front of the Dutch Embassy in Moscow on July 18. Hide Caption 25 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Students attend a prayer July 18 in Central Java, Indonesia. Their teacher John Paulissen was a passenger on Flight 17. Hide Caption 26 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – Russian President Vladimir Putin, center, and members of his government observe a moment of silence on Thursday, July 17. Hide Caption 27 of 28 Photos: Photos: Reaction to MH17 World reacts to MH17 crash – People pay tribute to the victims outside the Dutch Embassy in Kiev on July 17. Hide Caption 28 of 28

Photos: Malaysia Airlines Flight 17 crashes in Ukraine Photos: Malaysia Airlines Flight 17 crashes in Ukraine Debris from Malaysia Airlines Flight 17 sits in a field at the crash site in Hrabove, Ukraine, on September 9, 2014. The Boeing 777 was shot down July 17, 2014, over Ukrainian territory controlled by pro-Russian separatists. All 298 people on board were killed. In an October 2015 report, Dutch investigators found the flight was shot down by a warhead that fit a Buk rocket, referring to Russian technology, Dutch Safety Board Chairman Tjibbe Joustra said. Hide Caption 1 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Australian and Dutch experts examine the area of the crash on August 3, 2014. Hide Caption 2 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A woman walks with her bicycle near the crash site on August 2, 2014. Hide Caption 3 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Police secure a refrigerated train loaded with bodies of passengers from Malaysia Airlines Flight 17 as it arrives in a Kharkiv, Ukraine, factory on July 22, 2014. Hide Caption 4 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A pro-Russian rebel passes wreckage from the crashed jet near Hrabove on Monday, July 21, 2014. Hide Caption 5 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine – Wreckage from the jet lies in grass near Hrabove on July 21, 2014. Hide Caption 6 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A man covers his face with a rag as members of the Organization for Security and Co-operation in Europe and the Dutch National Forensic Investigations Team inspect bodies in a refrigerated train near the crash site in eastern Ukraine on July 21, 2014. Hide Caption 7 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Emergency workers carry a victim's body in a bag at the crash site on July 21, 2014. Hide Caption 8 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A piece of the plane lies in the grass in eastern Ukraine's Donetsk region on July 21, 2014. Hide Caption 9 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine An armed pro-Russian rebel stands guard next to a refrigerated train loaded with bodies in Torez, Ukraine, on Sunday, July 20, 2014. Hide Caption 10 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Ukrainian State Emergency Service employees sort through debris on July 20, 2014, as they work to locate the deceased. Hide Caption 11 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A woman covers her mouth with a piece of fabric July 20, 2014, to ward off smells from railway cars that reportedly contained passengers' bodies. Hide Caption 12 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Toys and flowers sit on the charred fuselage of the jet as a memorial on July 20, 2014. Hide Caption 13 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine People search a wheat field for remains in the area of the crash site on July 20, 2014. Hide Caption 14 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A woman walks among charred debris at the crash site on July 20, 2014. Hide Caption 15 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Emergency workers load the body of a victim onto a truck at the crash site on Saturday, July 19, 2014. Hide Caption 16 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Emergency workers carry the body of a victim at the crash site on July 19, 2014. Hide Caption 17 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A large piece of the main cabin is under guard at the crash site on July 19, 2014. Hide Caption 18 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Victims' bodies are placed by the side of the road on July 19, 2014, as recovery efforts continue at the crash site. International officials lament the lack of a secured perimeter. Hide Caption 19 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A man looks through the debris at the crash site on July 19, 2014. Hide Caption 20 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine An envelope bearing the Malaysia Airlines logo is seen at the crash site on July 19, 2014. Hide Caption 21 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Armed rebels walk past large pieces of the Boeing 777 on July 19, 2014. Hide Caption 22 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Ukrainian rescue workers walk through a wheat field with a stretcher as they collect the bodies of victims on July 19, 2014. Hide Caption 23 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A woman looks at wreckage on July 19, 2014. Hide Caption 24 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Pro-Russian rebels stand guard as the Organization for Security and Co-operation in Europe delegation arrives at the crash site on Friday, July 18, 2014. Hide Caption 25 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A woman walks through the debris field on July 18, 2014. Hide Caption 26 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Pro-Russian rebels stand guard at the crash site. Hide Caption 27 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Wreckage from Flight 17 lies in a field in Shaktarsk, Ukraine, on July 18, 2014. Hide Caption 28 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A man covers a body with a plastic sheet near the crash site on July 18, 2014. The passengers and crew hailed from all over the world, including Australia, Indonesia, Malaysia, Germany and Canada. Hide Caption 29 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A diver searches for the jet's flight data recorders on July 18, 2014. Hide Caption 30 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Coal miners search the crash site. Hide Caption 31 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Wreckage from the Boeing 777 lies on the ground July 18, 2014. Hide Caption 32 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine People search for bodies of passengers on July 18, 2014. Hide Caption 33 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A woman walks past a body covered with a plastic sheet near the crash site July 18, 2014. Hide Caption 34 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Belongings of passengers lie in the grass on July 18, 2014. Hide Caption 35 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine People inspect the crash site on Thursday, July 17, 2014. Hide Caption 36 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine People walk amid the debris at the site of the crash. Hide Caption 37 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Debris smoulders in a field near the Russian border. Hide Caption 38 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Fire engines arrive at the crash site. Hide Caption 39 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A man stands next to wreckage. Hide Caption 40 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Debris from the crashed jet lies in a field in Ukraine. Hide Caption 41 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Family members of those aboard Flight 17 leave Schiphol Airport near Amsterdam, Netherlands. Hide Caption 42 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A large piece of the plane lies on the ground. Hide Caption 43 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Luggage from the flight sits in a field at the crash site. Hide Caption 44 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A couple walks to the location at Schiphol Airport where more information would be given regarding the flight. Hide Caption 45 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Flight arrivals are listed at the Kuala Lumpur International Airport in Sepang, Malaysia. Hide Caption 46 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Debris from the Boeing 777, pictured on July 17, 2014. Hide Caption 47 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A man inspects debris from the plane. Hide Caption 48 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Wreckage from the plane is seen on July 17, 2014. Hide Caption 49 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A man talks with security at Schiphol Airport on July 17, 2014. Hide Caption 50 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine Wreckage burns in Ukraine. Hide Caption 51 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A man stands next to the wreckage of the airliner. Hide Caption 52 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine People inspect a piece of wreckage believed to be from Malaysia Airlines Flight 17. This image was posted to Twitter Hide Caption 53 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine People inspect a piece of wreckage believed to be from Malaysia Airlines Flight 17. This image was posted to Twitter. Hide Caption 54 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A piece of wreckage believed to be from Malaysia Airlines Flight 17. This image was posted to Twitter Hide Caption 55 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A piece of wreckage believed to be from MH17. This image was posted to Twitter Hide Caption 56 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine An airsickness bag believed to be from MH17. This image was posted to Twitter Hide Caption 57 of 58 Photos: Malaysia Airlines Flight 17 crashes in Ukraine A piece of wreckage believed to be from MH17. This image was posted to Twitter Hide Caption 58 of 58

JUST WATCHED Obama: Rebels supplied by Russia Replay More Videos ... MUST WATCH Obama: Rebels supplied by Russia 02:38

That means "we cannot rule out technical assistance from Russian personnel in operating the systems," she added.

Officials said regardless of whether Russian operatives were manning the system, Russia bears responsibility for the attack because of its military and political support for the rebels.

In recent weeks, Russia has intensified its delivery of sophisticated military equipment, officials said.

"While it may take us some time to firmly establish who shot down a plane filled with innocents, most (U.N. Security Council) members and most members of the international community have been warning for months about the devastation that would come if Russia did not stop what it started, if it did not rein in what it unleashed," Power said.

Another senior U.S. official said that the "responsibility is Russia's whether they had Russian personnel there or they gave them equipment and an instruction manual" on what to do.

"These separatist leaders are taking orders from Russia and (Russian President Vladimir Putin) has to realize the consequence of sending heavy and sophisticated weapons to a gang of sociopaths, extremists, violent thugs, nationalists and agents who are just given weapons and told to make chaos," the official said.

The same official said that over the past 24 hours, Moscow has played "the usual game of deflection," noting it has put out "nonsense stories to send people down a rabbit hole" and hamper the investigation.

"It's not going to work," the official said. "The outrage is too deep and the evidence, including videos of separatists bragging about this, is too damning. They will have a hard time explaining this away."

President Barack Obama warned that without a stop in support to the rebels, Putin would face more international sanctions.

The administration this week escalated sanctions on key business sectors of the Russian economy over Ukraine.

Photos: MH17: What they left behind Photos: MH17: What they left behind MH17: What they left behind – A birthday card found in a sunflower field near the crash site of Malaysia Airlines Flight 17 in eastern Ukraine, on Thursday, July 24. The passenger plane was shot down July 17 above Ukraine. All 298 people aboard were killed, and much of what they left behind was scattered in a vast field of debris. Hide Caption 1 of 16 Photos: MH17: What they left behind MH17: What they left behind – A classical music record is seen among the sunflowers on July 24. Hide Caption 2 of 16 Photos: MH17: What they left behind MH17: What they left behind – A shoe, appearing to be brand new, sits under foliage at the crash site. Hide Caption 3 of 16 Photos: MH17: What they left behind MH17: What they left behind – Two Dutch passports belonging to passengers lie in a field at the site of the crash on Tuesday, July 22. Hide Caption 4 of 16 Photos: MH17: What they left behind MH17: What they left behind – Clothing, sunglasses and chocolate are seen on July 22. Hide Caption 5 of 16 Photos: MH17: What they left behind MH17: What they left behind – More sunglasses and a travel guide lie in the field on July 22. Hide Caption 6 of 16 Photos: MH17: What they left behind MH17: What they left behind – A doll is seen on the ground on Saturday, July 19. Hide Caption 7 of 16 Photos: MH17: What they left behind MH17: What they left behind – A single shoe is seen among the debris and wreckage on July 19. There has been concern that the site has not been sealed off properly and that vital evidence is being tampered with. Hide Caption 8 of 16 Photos: MH17: What they left behind MH17: What they left behind – Pieces of a wristwatch lie on a plastic cover at the crash site. Hide Caption 9 of 16 Photos: MH17: What they left behind MH17: What they left behind – A toy monkey. Hide Caption 10 of 16 Photos: MH17: What they left behind MH17: What they left behind – Books, bags, a tourist T-shirt. Ukraine's government said it had received reports of looting, and it urged relatives to cancel the victims' credit cards. But a CNN crew at the scene July 19 said it did not see any signs of looting. Hide Caption 11 of 16 Photos: MH17: What they left behind MH17: What they left behind – Passports were scattered across the large field. Hide Caption 12 of 16 Photos: MH17: What they left behind MH17: What they left behind – Playing cards and euros are seen at the crash site. Hide Caption 13 of 16 Photos: MH17: What they left behind MH17: What they left behind – A travel guide and toiletries. Hide Caption 14 of 16 Photos: MH17: What they left behind MH17: What they left behind – Luggage on Friday, July 18. Hide Caption 15 of 16 Photos: MH17: What they left behind MH17: What they left behind – An empty suitcase is cordoned off near the plane's impact site on Thursday, July 17. Hide Caption 16 of 16

Putin and the Russian government "have to make a strategic decision," Obama said on Friday. "Are they going to continue to support violent separatists whose intent is to undermine the government of Ukraine? Or are they prepared to work with the government of Ukraine to arrive at a cease fire and a peace that takes into account the interests of all Ukrainians?"

U.S. officials said it was unclear whether the incident could be a turning point in Russia's support for the rebels, but stressed a tough message would be sent to Putin once the final determination is made about what happened regarding Malaysia Air Flight 17.

How will Putin respond ultimately, especially on personnel and weapons sent to Ukraine?

"If he ever had an intention of backing off, this could be an opportunity for him to do that," another U.S. official said. "I don't think he does have that intention, though."

Officials noted, however, the tragedy would likely close any gap between the United States and the European Union over how severe the international response should be toward Russia.

"This is very likely to harden views that Russia is not a problem," one official said. "If there were any Europeans who believe it had nothing to do with them, that Ukraine was merely a local issue, that will change."