NATO and Britain have pulled staff out of Afghan government institutions after the killing of two U.S. military advisers took the death toll from raging anti-U.S. protests to around 30, AFP reported.

The Taliban claimed responsibility for Saturday February 25 shooting, saying it was in revenge for the burning of Korans at a U.S.-run military base - an incident that forced U.S. President Barack Obama to apologise to the Afghan people.

In a day of violence across the country, a UN compound came under attack by thousands of demonstrators in northeastern Kunduz province, but they were driven back when police fired into the crowd.

Five people were reported killed in the attack, adding to the death toll from five days of often violent protests over the burning of Korans at the U.S.-run Bagram airbase.

The Pentagon said the killings were "unacceptable" and called on Afghan authorities to better protect coalition forces and curtail raging violence.

The United States, which leads a 130,000-strong military force fighting the Taliban-led insurgency in Afghanistan, has advisors throughout the Kabul government.

Britain said its embassy was also temporarily withdrawing all civilian mentors and advisors from Afghan government institutions in Kabul.