Pro-Russian separatists in eastern Ukraine agreed Friday to allow investigators access to the scattered crash site of a Malaysian airliner that was shot down, killing all 298 aboard.
U.S. intelligence officials confirmed that Malaysia Airlines Flight MH17 was downed by a surface-to-air missile near Ukraine's border with Russia on Thursday, but have yet to determine where that missile originated.
Separatists and Ukraine's government have both denied involvement.
No distress calls came from the Boeing 777 before it plummeted from the sky with 283 passengers and 15 crew members on board. The crash left a debris field stretching up to 10 miles, with victims and body parts strewn across the countryside.
Among the passengers on the flight were 173 Dutch nationals, 44 Malaysians and 27 Australians and 12 Indonesians.
Given that the overwhelming majority of the victims of the attack are from Holland, Malaysia Airlines is sending 40 staff members to Amsterdam "to support the families," the airline said in a statement.
Malaysian Airlines officials have so far not identified any Americans among the passengers, although they cautioned Friday that some nationalities have still not been verified.
"We continue to seek information to determine whether there were any American citizens on board," the White House said in a statement late Thursday.
In the same statement, the White House also raised concerns that the evidence at the crash site might be tampered with.
The plane was shot down over Ukraine's war-torn Donetsk region, which has seen months of fierce fighting between Ukraine and pro-Russian militants. The already difficult task of determining the cause of the crash will be made even more challenging as investigators will be trying to work in the midst of a war zone.
However, pro-Russian separatists have agreed to give investigators safe access to the crash site and to provide them with assistance, the Organization for Security and Cooperation in Europe (OSCE) said in statement on its website. The militants have even agreed to "cooperate with the relevant authorities of Ukraine" on questions regarding the crash, the OSCE said.
The whereabouts of the plane's block box flight recorders was not immediately clear although there were reports that rescue workers had recovered one and that another found by separatists was handed over to Moscow, the Interfax news agency reported.
Rescue workers, police officers and even off-duty coal miners were searching the area around the crash site for bodies and debris Friday morning.
About 70 coal miners, dressed in overalls and covered with soot, joined the rescue effort near the rebel-held village of Rozsypne in the separatist Donetsk region, about 25 miles from the Russian border.
At least four bodies were seen in the streets of the village, and an Associated Press journalist saw bodies and body parts strewn across a sunflower field outside Rozsypne.
Earlier Friday, Australian Prime Minister Tony Abbott called for a "full, thorough and impartial international investigation."
"It's very important that we find out the facts and it's very important that we don't allow Russia to prevent an absolutely comprehensive investigation," Abbott said. "This is not an accident, it's a crime. Let me stress — it's not an accident it's a crime and criminals should not be allowed to be get away with what they've done."
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..
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.
Contributing: Oren Dorell in McLean, Va., Donna Leinwand Leger in Washington, D.C., Jabeen Bhatti in Germany and the Associated Press.