KABUL - A gunman has killed two US military advisers with shots to the back of the head inside a heavily guarded ministry building on Saturday, and NATO ordered military workers out of Afghan ministries as protests continued over the burning of copies of the Quran at a US army base.

The Taliban claimed responsibility for Saturday's Interior Ministry attack, saying it was retaliation for the Quran burnings, after the US servicemen - a lieutenant colonel and a major - were found dead on the floor of an office that only people who know a numerical combination can get into, Afghan and Western officials said.

The top commander of US and NATO forces recalled all international military personnel from the ministries, an unprecedented action in the decade-long war that highlights the growing friction between Afghans and their foreign partners at a critical juncture in the war.