Immigration officials told the BBC that he was interviewed last week at the Israeli embassy in Moscow. He has faced delays in renewing his UK visa.

His spokesman would not comment on reports citizenship had been granted.

Mr Abramovich, 51, would be the richest person in Israel.

His UK investor visa reportedly expired some weeks ago but the British government has refused to comment on his individual case.

The delay in issuing him a new one comes amid increased diplomatic tensions between London and Moscow after the poisoning of former Russian spy Sergei Skripal in southern England.

Israeli media reports say he has been given an identity card in Israel under the Law of Return, which allows Jews to become citizens of Israel.

The Times of Israel said the interior ministry had confirmed Mr Abramovich arrived in Israel on Monday and that he had emigrated to the country.

He is a frequent visitor to Israel and bought a hotel in Tel Aviv in 2015 that reports say he has turned into a residence.

Israel passport holders are allowed to enter Britain without a visa for short stays.

Mr Abramovich is worth $11.5bn (£8.6bn), according to Forbes magazine. The move could pay off financially as new Israeli citizens are exempt from paying tax on foreign income for 10 years.

One of Russia's richest people, he bought Chelsea FC in 2003
He reportedly sold dolls before making his fortune in oil in the 1990s after the collapse of the former Soviet Union
Mr Abramovich was a one-time business partner of the late tycoon Boris Berezovky, an associate of former Russian President Boris Yeltsin
Critics say the two businessmen used their Kremlin "family" ties to acquire key state companies for below market value
Mr Abramovich served as governor of Russia's Chukotka region
He is believed to be close to current Russian President Vladimir Putin