Joining the growing international demand for an impartial investigation into the shooting down of Malaysian Airlines jet MH17 in Ukrainian airspace by a surface-to-air missile, British Prime Minister David Cameron said that the Russian and Ukrainian governments should be part of this effort and “do whatever they can to get to the bottom of this horrific incident.”

"If, as seems possible, this was brought down then those responsible must be brought to account and we must lose no time in doing that," he said.

Nine Britons were among the 298, who were killed in the Boeing 777 crash.

The outcome of an investigation that will pin responsibility for the act of shooting down the jet – clearly an unintended target – will have profound short-and long-term implications for regional and transatlantic politics.

In a press release, the Trilateral Contact Group (that comprise senior representatives of Ukraine, the Russian Federation and the Organisation of Security and Cooperation in Europe), who were meeting in Kiev when the crash took place said that it held a video conference with separatist groups in Donetsk in eastern Ukraine.

The rebel groups, according to the press release, committed to “close off the site of the catastrophe and allow local authorities to start preparations for the recovery of the bodies”; provide safe access and security guarantees to national and international investigators; and, provide access and security to OSCE members.

Even as the enormity of the human tragedy is unravelling, a mass of contradictory information in the media space has led to unsubstantiated and speculative conclusions. The Ukrainian government has blamed the pro-Russian separatists, who it claims are in possession of the Russian-built BUK-M1 anti-aircraft missile systems that were used to shoot the jet down.

"At present it has yet to be ascertained beyond any doubt that it actually was a missile firing that resulted in the aircraft loss,” cautions Douglas Barrie, Senior Fellow for Military Aerospace at the London-based International Institute for Strategic Studies in an email response to a question from The Hindu. “If this does prove to be the case then the 9K37 BUK medium-range surface-to-air missile system is a credible candidate. This system is in the Ukrainian inventory and the separatists may have captured one or more."

The Ukrainian government has tried to bolster its case by releasing recordings of rebel commanders allegedly reporting to their Russian superiors on the success of their strike on an aircraft - and their dismay at learning that it was a commercial airliner.

The Russian government and the pro-rebel groups have denied this, and have called for an independent investigation.

Russian Foreign Minister Sergei Lavrov denied media reports that the black boxes recovered from the wreckage were taken to Moscow. He told a Russian media outlet that the analysis of the flight recorders “is the responsibility of ICAO [International Civil Aviation Organisation]; it’s the responsibility of those states, which have the most direct connection to this tragedy – the Netherlands, Malaysia and the states whose citizens were on board, and of course Ukraine.”