A source in Ukraine’s military intelligence agency on Sunday claimed responsibility for two attacks on Russia’s railway system over the weekend that derailed a train and killed three Russian officers.

The source told AFP that Ukraine’s GUR military agency had targeted “important logistical links in supplying the occupying forces in the Kharkiv and Sumy directions.”

Two trains in separate parts of Russia’s western Leningrad region derailed early Sunday, leaving a train driver dead and disrupting railway traffic, the region’s governor said.

The incidents came hours after an explosive device detonated on a section of rail track in Russia’s western Oryol region late Saturday, killing three people.

“Recovery efforts are under way following the derailment of a single diesel locomotive near Semrino station in Leningrad’s Gatchina district,” governor Alexander Drozdenko said on Telegram.

“The train driver was killed. He was trapped in the cabin, and died in an ambulance after being unblocked,” he added.

A freight train carrying 15 empty tank cars derailed on a section of track further south, but left no casualties, he said in an earlier post.

Russia’s railway network has been repeatedly rocked by derailments, blasts and fires that authorities blame on Ukrainian sabotage.

Kyiv does not typically claim responsibility but often cheers such attacks on, arguing Russia uses its train network to deliver troops and fuel to its forces fighting in Ukraine.