A Ukrainian military spokesman says government forces have captured two Russian officers who were operating in the rebel-controlled area.

Ukrainian military spokesman Andriy Lysenko said on Sunday that two Russians were taken prisoner in the town of Shchastia, not far from the rebel-controlled area. He would not provide further detail and said investigators were questioning the men.

A year-long conflict between Russia-backed separatists and government troops in eastern Ukraine has killed more than 6,100 people. Russia has repeatedly denied that it was supplying the separatists with rebels or recruits.