The forces of the Russian-led CSTO military alliance are ready if needed for a peacekeeping operation, a senior official said Friday, as pro-Kremlin fighters were beating back Kiev's troops in eastern Ukraine.

Troops from the Collective Security Treaty Organisation "are ready to participate in peacekeeping operations no matter how difficult," its chief Nikolai Bordyuzha was quoted as saying by RIA-Novosti news agency.

He said CSTO leaders could decide to deploy peacekeepers "on the territory of a member state or beyond."

In addition to Russia the CSTO includes Armenia, Belarus, Kazakhstan, Kirgyzstan and Tajikistan.

Russia has previously intervened in conflicts in the region calling its troops peacekeepers, including in Moldova and Georgia.