Counter-terror police in London investigating 'unexplained' death of man said to be Russian exile British media reported he was believed to be a Russian exile.

Counter-terrorism police are investigating an “unexplained” death of a man in his 60s found dead at a residential address in the London area, London police said Tuesday.

The counter-terrorism police were leading the probe "as a precaution because of associations that the man is believed to have had," the Metropolitan Police said. Police responded Monday night after reports that his body was found in the Kingston area of London, authorities said.

British media reported that the man was believed to be Nikolai Glushkov, a 69-year-old Russian exile who was close to a prominent critic of Russian President Vladimir Putin.

The Metropolitan Police said there was no evidence that suggested a link to last week's poisoning of former Russian spy Sergei Skripal and his daughter Yulia in Salisbury, England. The U.K. has said it was "highly likely" Russia was behind the poisoning, which left the pair in critical condition.

Glushkov was friends with Boris Berezovsky, a Russian oligarch who had criticized Putin and was found dead at his U.K. home in 2013, according to Sky News. A British inquest into Berezovsky's death concluded there was not enough evidence to determine how Berezovsky died, Sky News reported at the time.

Police in London said they believed they knew the identity of the deceased man but that the body had not yet been formally identified.