World leaders have urged Moscow, pro-Russian separatists and Ukraine to support a ceasefire in order to ensure international investigators have access to the crash site of a Malaysian airliner downed over Ukrainian territory.
A Friday statement from the White House said the U.S. National Transportation Safety Board and the FBI would contribute to any international investigation that may be carried out.
"It is critical that there be a full, credible, and unimpeded international investigation as quickly as possible. It is vital that no evidence be tampered with in any way and that all potential evidence and remains at the crash site are undisturbed," it said.
The statement forwarded the notion that the downing of the Malaysian commercial airliner occurred in the context of the Ukraine crisis, during which pro-Russia President Viktor Yanukovych was ousted in February by protesters seeking closer ties with the European Union.
Malaysia’s Prime Minister Razak Najib said during an emotional press conference in Kuala Lumpur on Friday morning that he had received a call from U.S. President Barack Obama, during which they had mutually agreed for a thorough investigation that will include an international team with full access to the crash site.
"No stone will be left unturned. If the plane has indeed been shot down, Malaysia will insist that the perpetrators be swiftly brought to justice,” Najib added.
In Germany Friday, Chancellor Angela Merkel called for an independent investigation to "begin as soon as possible.”
“For such an independent investigation, a truce is necessary,” she told journalists in Berlin.
She underlined that the tragic incident has shown once again the importance of reaching a political solution in Ukraine and called on Russia to play its part.
“Russia and the Russian president should make their contribution to reach a political solution. Ways for a permanent and mutual ceasefire must be found,“ she said.
“The developments of the last week showed that this is a difficult path, but from my point of view, there is no alternative to a diplomatic and political solution.”
Meanwhile, British Defence Secretary Phillip Hammond sent his condolences to those who lost friends and family in the crash and backed calls for an international investigation.
He said he did not want to “speculate” as to what had happened or about the exact number of U.K. nationals on board.
Both Merkel and U.S. Secretary of State John Kerry on Friday paid condolences to the families of the victims of the downed commercial airliner - on which there were four German citizens.
"We are horrified by the crash of Malaysia Airlines flight MH17. There are no words adequate to express our condolences to the families of the nearly 300 victims," said Kerry.
He also noted that they have been reviewing whether any American citizens were aboard the flight.
Malaysia Airlines Boeing 777 flight MH17 was downed Thursday night close to Ukraine's border with Russia with 295 people on board. Ukraine President Petro Proshenko has blamed "terrorists" for "shooting down" the plane, which was flying from Amsterdam to Kuala Lumpur at an altitude of 10,100 meters.
The Ukraine government uses the term "terrorists" in relation to pro-Russia separatists it is battling who are seeking to unite the east of Ukraine with Moscow.
Meanwhile, Russian President Vladimir Putin has held Ukraine responsible for the crash, saying in a Friday statement that "the tragedy would not have happened if there were peace on this land, if the military actions had not been renewed in southeast Ukraine.”
The disappearance adds to a woeful year for Malaysia's national carrier, following the disappearance of Beijing-bound flight MH370 after it left Malaysian airspace March 8.
A total of 239 people were on board the flight, including 12 crew and 153 Chinese citizens.
Despite the most intensive search in commercial aviation history, Malaysia's efforts to find the plane have been heavily criticized by media and the family of passengers.
* Anadolu Agency correspondents Ayhan Simsek in Berlin, Assed Baig in London and Prem Kumar in Kuala Lumpur contributed to this report.