NATO has recalled all staff working at Afghan government ministries after two U.S. officers were shot dead at close range inside a secure command center at the Interior Ministry in Kabul.
NATO said the decision to order the recall came "for obvious force protection reasons." It said the official account indicated a member of the Afghan security forces turned his weapon on the Americans who worked as advisers at the ministry.
The Afghan Taliban claimed responsibility for the shooting, and said the attack was retaliation for the burning of Qurans by NATO personnel a week ago. The incident has inflamed passions throughout the country and led to rioting in which dozens of people have died.
The Pentagon described as "unacceptable" the killing of the two officers. A spokesman for U.S. Defense Secretary Leon Panetta said his Afghan counterpart, Defense Minister Abdul Rahim Wardak, had called to apologize for the incident.
Later Saturday, President Barack Obama called his top commander in Afghanistan, General John Allen, to discuss the ongoing violence in the country, as well as the killing of the two Americans. Mr. Obama expressed his condolences to General Allen and to the families of the victims. He also welcomed a statement by Afghan President Hamid Karzai calling for "dialogue and calm."
A NATO spokesman, Brigadier General Carsten Jacobson, said a gunman "turned his weapon against" the Americans. There was no word on the fate of the gunman or whether anyone else was involved in the shooting. "What we can confirm so far is that in the inner city of Kabul an individual pulled his weapon and opened fire on members of the International Security Assistance Force. We can confirm that two ISAF personnel were killed in this incident and at this present stage it is too early before the information process to the next of kin is done to talk about any further details of those who perished," he said.
Violence continued across Afghanistan Saturday, in a fifth straight day of protest over the burning of Qurans.
Hundreds of rock-throwing demonstrators attacked a United Nations compound in northern Kunduz province. Local officials said at least three people were killed and 47 were wounded in the rioting.
Since Tuesday, when reports first surfaced about the Quran-burning incident at Bagram Air Base near Kabul, at least 27 people have died in violent circumstances, including at least two other NATO service members whose killing was claimed by the Taliban.
President Obama and other U.S. officials have apologized for any desecration of the Muslim holy book, but that has done little to quiet the outrage in Afghanistan and neighboring Pakistan.
NATO is conducting a full investigation of the incident, but has not issued a detailed statement yet. Media reports quoted unnamed Western officials as saying it appeared that the copies of the Quran in question and other Islamic readings in the library at Bagram were being used to fuel extremism, and that detainees were writing on the documents to exchange extremist messages.
In a separate incident in western Badghis province, Afghanistan's defense ministry said six Afghan soldiers died and 16 were wounded Saturday while trying to defuse a roadside bomb.
Some information for this report was provided by AP, AFP and Reuters.