The Kremlin said on Monday that the United States had "never given up" trying to spy on Russia, after leaked Pentagon documents appeared to show Washington had collected data on Russian intelligence.

Asked whether the Kremlin was worried about the leaks, spokesman Dmitry Peskov said: "Our special services and counter-intelligence unit carry out their functions. The U.S. has never given up trying to conduct intelligence activities on us."

(Reporting by Reuters; Editing by Kevin Liffey)