MIRANSHAH, Pakistan (Reuters) – Pilotless U.S. drones fired 18 missiles into a Pakistani sanctuary for al Qaeda and Taliban fighters on the Afghan border on Tuesday, killing at least 10 militants, residents and security officials said.

The United States has stepped up drone strikes on militant sanctuaries on the Pakistani side of the Afghan border since a December 30 suicide bombing killed seven CIA employees at a U.S. base in the eastern Afghan province of Khost.