The Kremlin was not responsible for supplying weapons to separatist rebels accused of bringing down Malaysia Airlines flight MH17 over eastern Ukraine, Russia's ambassador to London has said.
Alexander Yakovenko said claims by Kiev and Washington that Moscow and the pro-Russia separatists were behind the downing of the plane did not "hold water".
Speaking at a news conference at the Russian embassy, he warned that any attempt by the West to impose further sanctions against Russia would be seen in Moscow as evidence of a "cover-up".
"Russia doesn't supply weapons to local de facto (separatist) authorities in eastern Ukraine. No evidence whatsoever has been presented that the Russian government has been doing this," he told reporters.
"Needless to say, we will consider any further sanctions against us and the measures of political pressure as the clear evidence that our Western partners cannot substantiate their allegations and (are) eager to engage in a cover-up of the true causes of the MH17 tragedy."
In comments apparently designed to goad Western governments and their Ukrainian allies, Mr Yakovenko said the case against Russia and the separatists had been largely built on photographs and messages from social media sites which had since "proved to be forgeries".
He accused the government in Kiev of trying to show that Moscow had been supplying the rebels with "a powerful air defence system" ahead of talks by EU ministers to discuss further sanctions.
"Too much evidence directs to explaining the tragedy as something that was aimed at framing up Russia on the eve of the EU ministerial that went terribly wrong," he said.
While he insisted that Russia was not trying to prejudge the outcome of an international investigation into the causes of the crash, he said Moscow's own evidence suggested that there were Ukrainian missile systems in the area at the time.
"As proved by the Russian military's data, the Ukrainian forces moved two of their systems closer to the position of the local authorities and after the crash moved them back. Kiev cannot refute this evidence," he said.
Mr Yakovenko conceded that the separatists could have seized weapons from the Ukrainian formations, but said that was nothing to do with Moscow.
"Ukraine is full of weapons. Some of the weapons were captured from the Ukrainian army. This is the fact of the civil war. But Russia has nothing to do with that. To make a connection with Russia (is) unacceptable," he said.
He warned proposals for far-reaching economic sanctions backed by Britain and the US would be "illegal, unreasonable and counter-productive" and could precipitate a new phase in the global financial crisis.
"In my view the sectoral sanctions against Russia will trigger a long anticipated endgame of the present global crisis," he said.
The ambassador also took a swipe at suggestions that the forthcoming public inquiry into the killing in London of the dissident former KGB officer, Alexander Litvinenko, could take some evidence in secret.
"We will never accept any public judgment based on the evidence that hasn't been subject to to competitive process in the court," he said.
The Dutch Safety Board (DSB) which is leading the investigation into the MH17 disaster, said that the black box flight data recorder (FDR) recovered from the crash scene was slightly damaged but the memory module was intact.
The DSB went on: "Furthermore, no evidence or indications of manipulation of the recorder was found. Following the examination, the data was successfully downloaded and the FDR contained valid data of the flight."
Yesterday the DSB had said that the black box cockpit voice recorder (CVR) had also been damaged but that it had also been successfully downloaded and had also contained valid flight data.
"The data from both recorders will be further analysed and combined," the DSB said today.
The black boxes - actually orange in colour - have been analysed by the UK Air Accidents Investigation Branch (AAIB) and by international experts at the AAIB's headquarters at Farnborough in Hampshire.
The DSB said today: "A thorough analysis of the information obtained will take time and the results will be included in the investigation."
EU member states agreed to add 15 individuals and 18 entities to the list of those subject to asset freezes - though their identities are yet to be published.
Ambassadors meeting in Brussels are also examining the targeting of state-owned Russian banks as part of an effort to tighten the screw of sanctions.
Capital markets, energy and arms are among other areas from which Moscow could be excluded.
Foreign ministers agreed on Tuesday to beef up the existing regime but talks continue over the detail amid concerns that some member states could end up being harder hit than others by the loss of trade.
The move came as Ukraine's already fragile political state was plunged into further confusion by the resignation of prime minister Arseniy Yatsenyuk and his government after he lost the support of two coalition partners.
It opens the way for fresh elections in the troubled country, where pro-Russian forces control parts of the east.