French authorities say they have seized two yachts belonging to Russian billionaire Boris Berezovsky. The seizure of the yachts on the French Riviera came at the request of Russian prosecutors who are pursuing Berezovsky for fraud.

Berezovsky fled to the UK in 2000 after falling out with then-president Vladimir Putin. Moscow has demanded his extradition but the British government granted him political asylum in 2003.

An anonymous court source told AFP that seizing the two boats was part of a Russian investigation into fraud, money-laundering and a conspiracy charge which French officials describe as “criminal association”.

The boats include a 49m (160ft) yacht and a smaller vessel at Golfe-Juan.

“The question is what to do next. Either Russian seamen will take them via the Black Sea, or they will leave them here. But there is no question of us paying for their upkeep,” local prosecutor Jean-Michel Cailleau told AFP.

The value of the yachts is estimated at US$20m. Paintings belonging to Berezovsky were also seized.