Russia is concerned about a U.S. plan to deploy spy drones in Poland, RIA news agency cited a Russian deputy foreign minister as saying on Thursday.

Sergei Ryabkov also said Washington's move demonstrated what he called its "aggressive intentions."

On Wednesday, U.S. President Donald Trump promised Polish President Andrzej Duda that he would deploy 1,000 U.S. troops to Poland, a step sought by Warsaw to deter potential aggression from Russia.