The court identified the three men as Mikhail Golovachuk, Ruslan Khansvyarov and Dmitry Korotayev.

In a rare apparent demonstration of US-Russian collaboration at a time of high tensions between the two over Ukraine, Russian authorities detained and charged the REVil group’s members this week.

A police and FSB domestic intelligence operation searched 25 addresses, detaining 14 people, the FSB said yesterday, listing assets it had seized including US$600,000 of computer equipment and 20 luxury cars.

The US welcomed the arrests.

The US said in November it was offering a reward of up to US$10 million for information leading to the identification or location of anyone holding a key position in the REvil group.

A source familiar with the case told Interfax the group’s members with Russian citizenship would not be handed over to the US.