WARSAW, June 26 (RIA Novosti) - Poland has accused Russia of building up a covert network of agents, the country's military intelligence chief said Tuesday.

Antoni Macierewicz said Poland has not seen as many Russian spies since the Cold War era.

"Penetration by Russian [intelligence] services and secret agents in Poland has grown substantially, especially in the past few years," he said in an interview with the Gazeta Polska weekly. He also said that the increase in agents in Poland is demonstrated by their relentless search for new sources of information, and aggressive tactics, among other things.

The claims have been backed up by British intelligence services, who claim that activity by Russian agents has returned to Cold War levels.

He said a report recently released by Polish special services lists 800 military servicemen who received training at Russia's Main Intelligence Directorate (GRU) when Poland was a member of the Warsaw Pact.

The Russian special services have made no comment on Macierewicz' claims.