British police announced Saturday they have launched a full investigation into the "unexplained death" of 67-year-old Berezovsky.

An emergency medical team confirmed reports, saying they had been called to a home in Ascot, near London, on Saturday. The cause of death, they said, was unconfirmed.

"We were called at 3:18 p.m. (1518 GMT) today by a caller who was concerned about the welfare of a gentleman at an address in Ascot," a spokesperson for the South Central Ambulance Service, told the news agency AFP.

"We sent a number of ambulance officers and one ambulance to the address," the spokesperson said. "The man was confirmed deceased at the scene."

Berezovsky, a former Kremlin insider who later became a critic of Russian President Vladimir Putin was living in London, having been granted asylum.

Egor Schuppe, Berezovsky's son-in-law, told the broadcaster Russia Today that he had been depressed and failed to keep in contact with family and friends.

In December, Berezovsky lost a multimillion-pound legal battle with Chelsea Football Club owner Roman Abramovich. He was ordered by a court to pay 35 million pounds ($56 million, 43.1 million euros) in legal costs after losing a damages claim, the High Court in London said.

He had been convicted and jailed on embezzlement charges in absentia by Russian courts.

jlw/kms (Reuters, AFP, dpa)