Doug Stanglin and Gary Strauss

USA TODAY

Officials from several countries vow to quickly determine who's behind Thursday's downing of Malaysia Airlines Flight MH-17 and the deaths of all 298 aboard.

U.S. intelligence officials confirmed that the crash was caused by a surface-to-air missile near Ukraine's border with Russia, but have yet to determine where it originated. The incident already is inflaming tensions between the two countries and escalating political rhetoric elsewhere.

It was "not an accident, it was blown out of the sky,'' said Vice President Joe Biden.

Malaysia Airlines said Ukrainian air traffic control lost contact with Flight MH17 about 30 miles from Russia. There were no distress calls as the Boeing 777, carrying 283 passengers and 15 crew, began to break apart as it fell from the sky in the world's deadliest aviation incident since 9/11.

Crash victims and body parts were strewn among burning debris up to 10 miles away. Among the dead: 154 Dutch nationals, 27 Australians, 11 Indonesians, six Brits, four Germans, four Belgians, four French, three Filipinos and a Canadian. Malaysian Air officials have so far not identified any Americans among the passengers, although they cautioned that some nationalities have still not been verified.

The White House said late Thursday night that "We continue to seek information to determine whether there were any American citizens on board."

The crash site is in Ukraine's war-torn Donetsk region, where political unrest and scattered fighting between Ukraine and pro-Russian militants has festered for months. After the downing of several Ukraine aircraft in recent days, accusations, blame and finger-pointing over Thursday's crash was fevered.

Ukrainian President Petro Poroshenko called the crash "an act of terrorism' and demanded an international investigation. Ukrainian officials said they had intercepted telephone calls of a separatist leader discussing the crash with Russian military intelligence officers. Separatists initially believed they had downed a military cargo plane, according to the SBU, Ukraine's main security agency.

But Russian President Putin blamed the incident on Ukraine's government, which "carries responsibility for this horrible tragedy."

"We will do everything – everything that depends on us, in any case – to ensure that an objective picture of the events becomes accessible for our public and for the Ukrainian public and the entire world," Putin said.

In brief remarks at an appearance in Wilmington, Del., President Obama called the incident a "terrible tragedy" and said the U.S. will offer "any services it can" to determine what happened.

Said Malaysian Prime Minister Najib Razak; "We must and we will find out precisely what happened to this flight. No stone will be left unturned."

The crash occurred two hours after the flight departed Amsterdam at about 12:15 p.m. local time. It's the second disaster involving a Malaysia Air Boeing 777 this year. On March 8, Flight 370 disappeared with 239 passengers and crew aboard on a flight from Kuala Lumpur to Bejiing. Despite one of the most extensive searches in flight history, Flight 370 has yet to be found.

Anton Gerashenko, an adviser to Ukraine's Interior Ministry, said on Facebook that Flight MH17 was hit by a BUK anti-aircraft missile. Usually vehicle-mounted, the BUK can simultaneously track and strike multiple targets at different directions and altitudes, according to military think tank Globalsecurity.org.

A separatist leader in Donetsk denied that rebel forces had the capability to bring down a high-flying aircraft. Alexander Boroday, chairman of the Council of Ministers of the self-proclaimed Republic of Donetsk, called the incident a provocation by the Ukrainian military, Russia's Interfax news agency reported.

"Self-defense forces have no air-defense, which could target transport aircraft at that height," he told Interfax.

On Wednesday, a Russian military plane allegedly shot down a Ukrainian Su-25 jet fighter over Ukrainian territory, forcing the pilot to eject. Pro-Russian rebels claimed responsibility for hitting a second Su-25 with a portable surface-to-air missile. The pilot managed to land the plane safely.

"There have been Ukrainian helicopters and aircraft operating under the assumption of limited separatist capabilities,'' said Damon Wilson, a Russia and Ukraine expert in the administrations of George W. Bush and Bill Clinton. "They've learned quite rudely that the separatists have more advanced weapons."

Separatists have used a version of Russia's Grad rocket that Russian military only began using in January, Wilson said, citing sources in "U.S. government circles."

"This is not older, former equipment but among the most recent Russian equipment used in the Russian military," said Wilson, now deputy executive vice president at the Atlantic Council, a Washington think tank.

German, British and French airlines say they are keeping flights from crossing the region.

In Kuala Lumpur, several relatives of those aboard the jet came to the international airport.

A distraught Akmar Mohamad Noor, 67, said her older sister was coming to visit the family for the first time in five years. "She called me just before she boarded the plane and said 'see you soon,'" Akmar said.

Several passengers were heading to an international AIDS conference in Australia.

Australian Foreign Affairs Minister Julie Bishop said Friday that several people on board the Boeing 777 were en route to Melbourne to attend next week's conference.

The International AIDS Society issued a statement expressing "sincere sadness" that several of its colleagues and friends were on board the plane.

Bishop says at least 27 Australians were on board. The aircraft was scheduled to continue flying to the western Australian city of Perth after stopping in Kuala Lumpur.

Contributing: Oren Dorell in McLean, Va., Donna Leinwand Leger in Washington, D.C., Jabeen Bhatti in Germany and the Associated Press.

Follow Stanglin on Twitter: @dstanglin, Strauss @gstrauss_