Story highlights International observer: "There doesn't seem to be one commander in charge"

Dutch Prime Minister calls crash site problems "downright disgusting"

Ukrainian PM claims "someone well-trained" fired missile at Flight 17

Rebels, Russia of trying to destroy evidence, Ukrainian officials say

Nobody knows how many bodies from the Malaysia Airlines Flight 17 crash have been moved, where they were taken or exactly who moved them, the spokesman for a group of international observers told CNN on Saturday.

Michael Bociurkiw of the Organization for Security and Co-operation in Europe told "Erin Burnett OutFront" the group went to the crash site in a remote section of eastern Ukraine on Saturday and saw men moving an unknown number of body bags.

It's hard to get reliable information because several groups of pro-Russian separatists -- some of them masked -- control the area, he said. "But there doesn't seem to be one commander in charge."

Separatists are suspected of shooting down the plane with a Russian-made surface-to-air missile on Thursday.

Three air crash investigators from Ukraine accompanied the OSCE observers but didn't have much time to do their work, he said. "They need a lot more time and a lot more freedom of access," Bociurkiw said.

Where victims were from

Pressure on Putin

More world powers have deplored the situation and asked Russian President Vladimir Putin to use his influence on the separatists.

"Yesterday, the [OSCE] monitors were allowed only 75 minutes at the site," the U.S. State Department said in a statement released Saturday night. "Today, they were allowed less than three hours. ...

"The site is not secure, and there are multiple reports of bodies being removed, parts of the plane and other debris being hauled away, and potential evidence tampered with. This is unacceptable and an affront to all those who lost loved ones and to the dignity the victims deserve."

British Prime Minister David Cameron wrote a Sunday Times op-ed piece urging Putin to somehow make the crash site more accessible and calm the strife between Ukraine and the separatists. German Chancellor Angela Merkel and Dutch Prime Minister Mark Rutte spoke out as well.

I want to see results in the form of unimpeded access and rapid recovery," Rutte said in a press briefing. Nearly two-thirds of the people on the jetliner, which was en route from Amsterdam to Kuala Lumpur, were Dutch.

Rutte called images of people rummaging through the debris and belongings of victims "downright disgusting."

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'A very intense conversation'

Rutte told reporters of what he called "a very intense conversation" with Putin on Saturday in which he told the Russian leader "the opportunity expires to show the world that he is serious about helping."

Meanwhile, U.S. Secretary of State John Kerry spoke with his Russian counterpart, Foreign Minister Sergey Lavrov, to urge Moscow to get the rebels to stop fighting and talk peace, and also provide full access to the crash site.

The United States has said a Russian-made surface-to-air missile fired from the rebel territory took down the Malaysia Airlines Boeing 777 with citizens from more than 10 nations aboard.

The missile systems are the size of tanks, have treads like tanks and weigh around 50 tons. They require large, specialized military vehicles to transport them.

U.S. officials believe the missile systems may have been moved back across the border into Russia, CNN foreign affairs reporter Elise Labott said Saturday.

Russia has denied any involvement, and Putin said Ukraine's military campaign against the separatists was to blame. He also has called for a "thorough and objective investigation" of the crash.

Counter-accusations

Since the crash, the Ukrainian government and rebels have traded bitter accusations over who was responsible and what has been done since. Ivan Watson, a CNN international reporter, called it "an information war."

Vitaly Nayda, counterintellligence chief for Ukraine's Security Service, told reporters in Kiev that a Russian-made Buk M1 missile system had shot down the Malaysian airline.

He claimed that three Buk surface-to-air antiaircraft missile systems had crossed from Russia to Ukraine prior to the downing of Flight MH17, accompanied by Russian nationals who, he said, were the ones operating the sophisticated weaponry. All three Buk missile systems are no longer in Ukrainian territory, according to Nayda.

Prime Minister Arseniy Yatsenyuk, in an interview with CNN on Saturday, also suggested that whoever operated the missile system received expert training.

"This is not the Russian-led drunk terrorist who pressed the button," he said. "This is someone well-trained. Someone who knows how this machine works. Someone who has experience."

'Crime against humanity'

Ukraine and the international community "will find out all responsible for this international crime, and those who supported them, because this is (a) crime against humanity, and the building of (the) International Criminal Court is very big," Yatsenyuk added.

Even the local head of the rebels conceded for the first time Saturday that the plane got shot down. But Alexander Borodai reiterated that his forces did not do it. He told reporters the rebels lacked the firepower to hit an airplane so high up.

According to government officials, the rebels also removed debris and 38 bodies from the scene as part of an attempt to cover up what happened, and money, jewelry and other items had been looted from the dead. They urged relatives to cancel the credit cards of victims.

Borodai, the rebel leader who calls himself the prime minister of the self-styled Donetsk People's Republic, denied that his forces removed any bodies.

"There is even a house where a body fell, the landlord asked us to remove, and we haven't because we are not allowed to move anything," he said.

A CNN crew at the scene Saturday said it did not see any signs of looting or the rebels rummaging through items at the crash site.

Access an issue

The fields where the plane came down Thursday, near the town of Torez in the Donetsk region, are in a volatile rebel-controlled area, making access to the scattered debris, bodies and body parts difficult.

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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

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Ukrainian officials blamed the security issues on factionalism and lack of internal communication among the pro-Russian rebels.

Some rebel groups in the area have agreed to give OSCE experts access to the wreckage, while others have not, a spokesperson for Donetsk Gov. Oleksandr Omelchenko said. He said the conditions make it impossible to know whether all the armed rebels have left an area.

This is consistent with what CNN journalists have seen at the debris field. Earlier Saturday, a rebel commander on the ground gave a group of CNN journalists permission to approach the wreckage, but within 30 minutes warning shots were heard and the journalists were told to leave.

Black boxes

One key issue for investigators is the location of the plane's flight data recorders, which may hold crucial data.

The Ukrainian government said Friday that the so-called black boxes are still in Ukrainian territory but didn't clarify whether they were in Ukraine's possession.

Bociurkiw of the OSCE said no one at the crash site was able to tell his people where the recorders might be.

Malaysian investigators also touched down in Kiev on Saturday to try to get the bottom of what happened to the jetliner.

But Malaysia's official news agency Bernama said they were still negotiating with pro-Russian rebels over access for their 131-member team.

Malaysian Transport Minister Liow Tiong Lai said Saturday in Kuala Lumpur that Malaysia was "deeply concerned that the crash site has not yet been properly secured."

"There are indications that vital evidence has not been preserved in place," he said.

The full list of the passengers was released Saturday. According to a final breakdown from Malaysia Airlines, 193 of those killed were from the Netherlands, including one who had dual U.S.-Dutch citizenship.

There were also 43 victims from Malaysia, including the plane's 15 crew; 27 from Australia; 12 from Indonesia; 10 from the United Kingdom, including one who had dual UK-South African citizenship; four each from Germany and Belgium; three from the Philippines and one each from Canada and New Zealand.

Eighty of the victims were children, the United Nations said.

DNA evidence

In the Netherlands, dozens of police officers are now visiting all the families of the victims. They will gather specific information that will help identify the victims, such as DNA samples, details of tattoos and dental records, Dutch police said. A Dutch forensics team has already arrived in Ukraine.

The FBI is sending two investigators to work on the case, a U.S. law enforcement official said, but the Ukraine government will be in charge of the investigation.

Australia is sending six foreign affairs officers to Kiev to assist in the investigation, the country's Prime Minister Tony Abbott said Saturday.

The Kremlin has criticized Abbott over his harsh words on possible Russian involvement in the tragedy. He repeated them Saturday.

"Australia takes a very dim view of countries which facilitate killing of Australians, as you'd expect us to. We take a very, very dim view of this and the idea that Russia can wash its hands of responsibility, because this happened in Ukrainian airspace, just does not stand serious scrutiny," Abbott said.

Obama's focus on Russia

U.S. President Barack Obama also said Russia likely bears some of the responsibility, noting rebel fighters couldn't have operated the surface-to-air missile "without sophisticated equipment and sophisticated training, and that is coming from Russia."

A day before MH17 came down, Obama announced expanded sanctions against a number of major Russian companies in response to Russia's actions in Ukraine.

In an apparently retaliatory move, Russian Foreign Ministry spokesman Alexander Lukashevich said Saturday that Russia had added the names of 13 American citizens to a list that bans them from entering Russia. The list includes U.S. Rep. Jim Moran, D-Virginia.