"Malaysia has been formally invited to participate, and will send two senior accredited representatives to assist, he said."
Moscow/Kiev/Kuala Lumpur, July 18 - Russia and Western-backed Ukraine sparred Friday over who shot down a Malaysian airliner killing all 298 people on board as the UN sought a truce in eastern Ukraine.
As Malaysia and the Netherlands -- 189 of the dead were Dutch -- plunged into sorrow, the Malaysia Airlines said four of the victims were yet to be identified, Xinhua and other media reported.
Russia blamed Ukraine for the horrific disaster Thursday, saying Kiev should have never allowed a commercial jet to fly over a region enveloped in fighting between pro-Russian rebels and the military.
Flight MH17, a Boeing 777, crashed in the conflict-hit Donetsk region while flying from Amsterdam to Kuala Lumpur. It was the second disaster to strike Malaysia Airlines since a plane went missing mysteriously in March.
Among the dead were 189 Dutch, 44 Malaysians (including 15 crew), 27 Australians, 12 Indonesians, nine Britons, four Belgians and Germans each, three Filipinos, a Canadian and a New Zealander.
The nationalities of four others are yet to be verified.
According to the Russian defence ministry, Ukrainian anti-aircraft systems covered the airspace where the Malaysian plane was hit.
The area is covered by two Ukrainian S-200 long-range anti-aircraft missile systems and three Buk-M1 middle-range missile systems, said the ministry.
Russian military analysts say any of these systems could have been fired to bring down the MH17.
The Ukrainian National Security and Defence Council denied that Ukrainian forces had anything to do with the tragedy.
The Boeing 777 was beyond reach of the Ukrainian ground anti-aircraft systems, the council said.
Ukraine's security services also released what they claimed were intercepted telephonic conversations involving Russian security officers and Ukrainian rebels that suggested the rebels were involved.
Secretary of State John Kerry said the US was ready to offer help to any international investigation into the tragedy.
The US remains prepared to assist with a credible, international investigation any way we can, and we will continue to be in touch with all relevant partners as we seek the facts, he said.
British Prime Minister David Cameron urged the world to get to the bottom of what happened and how it happened to MH17.
It is an absolutely appalling, shocking, horrific incident that has taken place and we have got to get to the bottom of what happened and how it happened. We have some information but we need to find more, Cameron said in London.
German Chancellor Angela Merkel called for a ceasefire in Ukraine where pro-Russian militants have been fighting seeking independence.
It is, of course, important that those responsible are held to account, said Merkel. There are many, many indications that the aircraft was shot down. And that's why we need to take these things very, very seriously.
Russian President Vladimir Putin called for an immediate settlement of the Ukraine crisis.
The Kremlin quoted Putin as also saying that all details of the crash must be investigated thoroughly.
In Kuala Lumpur, Malaysian Transport Minister Liow Tiong Lai said Ukraine should probe the circumstances that led to the crash.
Malaysia has been formally invited to participate, and will send two senior accredited representatives to assist, he said.
Liow said Malaysia Airlines will take its responsibilities towards the next of kin of the victims seriously. It has arranged about 40 staff to be flown to Amsterdam to support the distraught families.