(Adds Biden, Putin, Najib, Ukrainian accusations against Russia)
* Ukraine says Russian officers help rebels shoot down airliner with 295 aboard
* U.S. VP Biden says it was "blown out of the sky"
* Rebels deny role, though have said recently they have such missiles
* Malaysia Airlines MH17 en route from Amsterdam to Kuala Lumpur
* Raises stakes in East-West confrontation over Ukraine
By Anton Zverev
HRABOVE, Ukraine, July 17 (Reuters) - A Malaysian airliner was brought down in eastern Ukraine on Thursday, killing all 295 people aboard and sharply raising the stakes in a conflict between Kiev and pro-Moscow rebels that has set Russia and the West at daggers drawn.
As the United States said the Malaysia Airlines Boeing 777 from Amsterdam to Kuala Lumpur was "blown out of the sky", probably by a ground-launched missile, Ukraine and Russia traded accusations of blame, cranking up global pressure for a way out of a bloody local conflict that risks fueling a new Cold War.
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.
But separatists have said that they took control of such a missile system last month and had used it to shoot down a Ukrainian military transport plane that was destroyed on Monday.
The scale of the disaster, which left scores of unsuspecting foreigners, adults and children, strewn lifeless across the muddy Ukrainian steppe, could prove a turning point for international pressure to resolve the crisis. It has killed hundreds in since protests toppled the Moscow-backed president in Kiev in February and Russia annexed the Crimea a month later.
The United Nations Security Council plans an emergency meeting on Ukraine on Friday, diplomats said. U.N. Secretary-General Ban Ki-moon urged a full international investigation.
Reuters journalists saw burning and charred wreckage bearing the red and blue Malaysia insignia and dozens of bodies strewn in fields near the village of Hrabove, 40 km (25 miles) from the Russian border near the rebel-held regional capital of Donetsk.
More than half of the dead, 154 people, were Dutch. Another 27 were Australian and 23 Malaysian.
The Ukrainian government, condemning an act of "terrorism", released recordings it said were of Russian intelligence officers discussing the shooting down of a civilian airliner by rebels who may have mistaken it for a Ukrainian military plane.
Russian President Vladimir Putin pinned the blamed on Kiev for renewing its offensive against the 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 down.
U.S. Vice President Joe Biden said the jet was "blown out of the sky" and a U.S. official said that, while its origin was unclear, a surface-to-air missile was probably responsible.
After the downing of several Ukrainian military aircraft in the area in recent months, including two this week, Kiev had accused Russian forces of playing a direct role. International air lanes had remained open, though only above 32,000 feet. The Malaysia plane was flying 1,000 feet higher, officials said.
U.S. President Barack Obama said it was unclear whether Americans were aboard. A Ukrainian official said there were 23.
As word came in of what Ukraine's Western-backed president called a "terrorist attack", Obama was on the phone with Putin, discussing a new round of economic sanctions that Washington and its EU partners imposed to try to force Putin to do more to curb the revolt against the Western-backed government in Kiev.
They noted the early reports during their telephone call, the White House said, adding that Obama warned of further sanctions if Moscow did not change course in Ukraine.
Malaysia Airlines said air traffic controllers lost contact with flight MH-17 in the afternoon as it flew over eastern Ukraine towards the Russian border, bound for Asia with 280 passengers and 15 crew aboard. Flight tracking data indicated it was at its cruising altitude of 33,000 feet when it disappeared.
That would be beyond the range of smaller rockets used by the rebels to bring down helicopters and other low-flying Ukrainian military aircraft - but not of the SA-11 system which a Ukrainian official accused Russia of supplying to the rebels.
Separatists have been quoted in Russian media saying they had acquired one. One group was quoted as saying that it used an SA-11 on Monday to bring down an Antonov An-26 turboprop plane - a loss that the Ukrainian forces had confirmed this week along with the downing of a Sukhoi Su-25 fighter on Wednesday.
"I was working in the field on my tractor when I heard the sound of a plane and then a bang," one local man at told Reuters at Hrabove, known in Russian as Grabovo. "Then I saw the plane hit the ground and break in two. There was thick black smoke."
An emergency worker said at least 100 bodies had been found so far and that debris was spread over 15 km (9 miles). People were scouring the area for the black box flight recorders and separatists were later quoted as saying they had found one.
Kiev complained that separatists who are the main force in the area prevented Ukrainian officials from reaching the site.
Malaysian Prime Minister Najib Razak demanded swift justice for those responsible and said the crash site must not be interfered with before international experts had access.
"MH-17 is not an incident or catastrophe, it is a terrorist attack," Ukrainian President Petro Poroshenko tweeted. He has stepped up his military campaign against the rebels since a ceasefire late last month failed to produce any negotiations.
One rebel leader, the self-styled prime minister in Donetsk, said they could agree a truce of two or three days to help with investigation of the incident.
Russia, which Western powers accuse of trying to destabilise Ukraine to maintain influence over its old Soviet empire, has accused Kiev's leaders of mounting a fascist coup. It says it is holding troops in readiness to protect Russian-speakers in the east - the same rationale it used for taking over Crimea.
Ukrainian Interior Ministry official Anton Gerashchenko said on Facebook: "Just now, over Torez, terrorists using a Buk anti-aircraft system kindly given to them by Putin have shot down a civilian airliner flying from Amsterdam to Kuala Lumpur."
The Buk - which means beech tree in Russia - is a 1970s vintage, truck-mounted, radar-guided missile system, codenamed SA-11 Gadfly by Cold War NATO adversaries. It fires a 5.7-metre (19-foot), 55-kg (110-lb) missile for up to 28 km (18 miles).
"There is no limit to the cynicism of Putin and his terrorists!" Gerashchenko wrote on the social media site. "Europe, USA, Canada, the civilised world, open your eyes! Help us in any way you can! This is a war of good against evil!"
He also published a photograph he said showed a Buk launcher in the centre of the town of Torez on Thursday. It was not possible to verify the image. On June 29, Russia's Itar-Tass news agency quoted a separatist spokesman in Donetsk as saying they had taken control of a Buk air-defence system.
The military commander of the rebels, a Russian named Igor Strelkov, had written on his social media page at 1337 GMT, that his forces had brought down an Antonov An-26 in the same area. It is a turboprop transport plane of a type used by Ukraine's forces. There was no comment on that from Ukrainian officials.
Flight MH-17 could have been in that area around that time, just over three hours after it took off from Schipol airport.
Several Ukrainian planes and helicopters have been shot down in four months of fighting in the region. Ukraine had said an An-26 was shot down on Monday and one of its Sukhoi Su-25 fighters was downed on Wednesday by an air-to-air missile - Kiev's strongest accusation yet of direct Russian involvement, since the rebels do not appear to have access to aircraft.
Moscow has denied its forces are involved in any way.
The loss of MH-17 is the second disaster for Malaysia Airlines this year, following the mysterious loss of flight MH-370. It disappeared in March with 239 passengers and crew on board on its way from Kuala Lumpur to Beijing.
In 2001, Ukraine admitted its military was probably responsible for shooting down a Russian airliner that crashed into the Black Sea, killing all 78 people on board. A senior Ukrainian official said it had most likely been downed by an accidental hit from an S-200 rocket fired during exercises.
In 1983, a Soviet jet fighter shot down a South Korean airliner after it veered off course into Russian air space and failed to respond to attempts to make contact. All 269 passengers and crew were killed.
In 1988, the U.S. warship Vincennes shot down an Iranian airliner over the Gulf, killing all 290 passengers and crew, in what the United States said was an accident after crew mistook the plane for a fighter. Tehran called it a deliberate attack. (Additional reporting by Richard Balmforth and Natalya Zinets in Kiev and Alissa de Carbonnel in Moscow; Writing by Alastair Macdonald; Editing by Peter Millership)
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