Russia has issued large numbers of exceptionally harsh judgements against its citizens convicted of aiding Ukraine since Moscow launched its offensive in February 2022.

One of the men, Dmitry Pospelov, had allegedly been cooperating with Ukraine's SBU security service since 2017, prosecutors said.

He moved to Crimea, where he worked installing and servicing security cameras in hotels. He gave the SBU access to the footage, allowing them to monitor roads used to move Russian military equipment, and provided data on users of an Internet provider.

Crimea's Supreme Court sentenced him to 13 years in a strict-regime penal colony.

The other man, Vladislav Afanasyev, was found guilty of giving money to support Ukraine's army and passing "photos and geographical coordinates of locations" of naval ships.

"This data was reliable" and could have been used to carry out attacks, prosecutors said. The court sentenced Afanasyev to 15 years in a strict-regime prison colony.