The Kremlin on Thursday declined to comment on media reports that a prisoner exchange between Russia and the United States was set to begin imminently.

Signs of a major prisoner exchange between Russia and Belarus on one side and the United States, Germany, Slovenia and Britain on the other multiplied on Thursday as over a half-dozen Russian dissidents and activists disappeared from their prisons.

"I still do not give any comments," Kremlin spokesman Dmitry Peskov told reporters at a regular press briefing.