(Recasts, adds details, context)
MOSCOW, Oct 12 (Reuters) - Russia accused the United States on Thursday of illegally building up its forces in Poland and the Baltic region, saying it had quietly deployed an entire armoured division in breach of the main pact that governs Moscow's relations with NATO.
The Russian Defence Ministry said the alleged breach had occurred when Russia was conducting large-scale military exercises called 'Zapad-2017" with ally Belarus last month.
Major-General Igor Konashenkov, a spokesman for the ministry, said in a statement that troops from the U.S. 3rd Armored Brigade Combat Team were meant to have rotated out of the region leaving their equipment to be manned by colleagues from the U.S. 2nd Armored Brigade Combat Team.
Instead, Konashenkov said, the 2nd Armored Brigade had quietly deployed to Poland with its own armoured vehicles, while tanks and armoured vehicles from the 3rd Brigade had stayed and could be manned within 2 hours by bringing in troops from the U.S. Ramstein Base in Germany.
"So despite declarations from NATO and the U.S. about 'the insignificant nature' of troops concentrated along the Russian border a mechanised division, rather than a brigade, has been deployed," said Konashenkov. (Reporting by Andrew Osborn/Polina Devitt; Editing by Dmitry Solovyov)