Russia's UK Ambassador Alexander Yakovenko has said there is "no evidence" Russia had supplied weapons to separatists in eastern Ukraine and said any use of sanctions would send the "wrong message" to Kiev.
Western sanctions would be "illegal" and "counter-productive" and hurt the global economy, he said.
Mr Yakovenko said it was "striking" how much the United States "relied on social media" in relation to the MH17 crash rather than "intelligence" sources.
He said the decision of the European Bank for Reconstruction and Development (EBRD) to halt cooperation with Russia over new investments was "unacceptable" and "harmful" to all parties.
The mother of the three Australian children killed on flight MH17 told a memorial service her "arms would always be reaching for them."
A woman has apparently posted pictures of herself on social media with mascara looted from the Malaysian Airlines flight MH17 crash site.
A large section of plane wreckage and everyday carry-on items like chocolates remain scattered among the wild flowers at the crash site.