Two United States advisers who were shot dead in Afghanistan's interior ministry by an Afghan colleague had been mocking anti-US protests over the burning of the Koran, a government source said.

The description of the shooting - which led to NATO pulling all its advisers out of Afghan government ministries - came amid renewed violence in a sixth day of anti-American demonstrations.

A protester was killed and seven US soldiers were wounded in a grenade attack on their base as France, announced its Kabul embassy was temporarily withdrawing all its civilian mentors and advisors from Afghan institutions for "safety reasons".