Russia's embassy in London today accused Britain of "deliberately" withholding information on probes into the targeting of several Russians on its soil, as the war of words between the two countries continues.
The embassy said it had asked the British Foreign Office for "detailed information" on the investigation into the March 12 murder in London of Russian exile Nikolai Glushkov.
The 68-year-old businessman, who had received political asylum in Britain after being jailed in Russia for money laundering and fraud, died from "compression to the neck", according to a post-mortem.
The death came a week after the nerve agent poisoning of former double agent Sergei Skripal and his daughter Yulia in the English city of Salisbury.
Britain has blamed the attack on Moscow, which has angrily denied involvement.
"Almost a month has passed since Mr Glushkov's death, and like it happened with Sergei and Yulia Skripal, the British side provided no information," the embassy said in a statement.
"Given our numerous requests, the only thing we can suggest is that it is done deliberately."