Relatives of passengers onboard the downed Malaysia Airlines flight MH-17 arrive at Kuala Lumpur International Airport in Sepang July 18, 2014. [Photo/Agencies]

HRABOVE, Ukraine - World leaders demanded an international investigation into the crashed Malaysian airliner over eastern Ukraine in which all 298 people on board were killed, a tragedy that could further heighten tensions between Russia and the West.

Shock, fear and sadness after MH17 crash

Malaysia Airlines plane crashes in Ukraine

One US official said Washington strongly suspected a surface-to-air missile that downed the Malaysia Airlines Boeing 777 on a flight from Amsterdam to Kuala Lumpur on Thursday was fired by Ukrainian separatists backed by Moscow.

There was no evidence Ukrainian government forces fired a missile, said the official, speaking on condition of anonymity. US Vice President Joe Biden, speaking in Detroit, said the passenger jet was apparently "blown out of the sky".

Australian Prime Minister Tony Abbott appeared to go further than other Western leaders in apportioning blame, demanding on Friday that Moscow answer questions about the "Russian-backed rebels" that he said were behind the disaster.

More than 20 Australians were among the many nationalities aboard Flight MH17. The Netherlands was the worst affected, with 154 Dutch citizens on the downed plane.

The plane crashed near the village of Hrabove about 40 km (25 miles) from the border with Russia near the regional capital of Donetsk, an area that is a stronghold of rebels who have been fighting Ukrainian government forces for several months.

Ukraine accused pro-Moscow militants, aided by Russian military intelligence officers, of firing a long-range, Soviet-era SA-11 ground-to-air missile. Leaders of the rebel Donetsk People's Republic denied any involvement and said a Ukrainian air force jet had brought down the intercontinental flight.

Russian President Vladimir Putin - at loggerheads with the West over his policies toward Ukraine - pinned the blame on Kiev for renewing its offensive against rebels two weeks ago after a ceasefire failed to hold. The Kremlin leader called it a "tragedy" but did not say who brought the Boeing 777 down.

DISBELIEF IN MALAYSIA

The loss of MH17 is the second for Malaysia Airlines this year, following the mysterious disappearance of Flight MH370 in March, which vanished with 239 passengers and crew on board on its way from Kuala Lumpur to Beijing.

In Malaysia, there was a sense of disbelief that another airline disaster could strike so soon.

"If it transpires that the plane was indeed shot down, we insist that the perpetrators must swiftly be brought to justice," Malaysian Prime Minister Najib Razak told a pre-dawn news conference in Kuala Lumpur.

"This is a tragic day, in what has already been a tragic year, for Malaysia."

US President Barack Obama, who spoke to Dutch Prime Minister Mark Rutte as well as other leaders, said evidence from the crash must remain in Ukraine so international investigators have a chance to look at all of it, officials said.

"The president and prime minister (Rutte) agreed on the need to assure immediate access to the site of the incident to international investigators in order to facilitate the recovery of remains and to carry out a thorough investigation," the White House said.

U.N. Secretary-General Ban Ki-moon also called for a transparent international investigation of the incident. The U.N. Security Council will discuss the issue on Friday.

Kiev complained that separatists prevented Ukrainian officials from reaching the site. Separatists were later quoted as saying they had found one of the black box flight recorders.

Financial markets were hit by worries of new geopolitical tensions, as Israel invaded the Gaza Strip on the same day.

Top 5 deadliest attacks on commercial airliners  Since 1967 more than 700 people have been killed in 19 separate incidents involving live-fire attacks, according to UK-based aviation consultancy Flightglobal Ascend.