US Defence Secretary Leon Panetta has called on the Afghan government to take decisive action to protect NATO forces and curtail violence sweeping the country, after two US military officers were shot dead inside Afghanistan's interior ministry.
The killings came as Afghanistan reels from a wave of bloody protests that have gripped the country for the past five days over the burning of copies of the Koran at a NATO base, an incident that NATO described as a tragic blunder.
Although killings by Afghan troops against NATO forces do happen periodically, the nature of the latest killings are particularly troubling for the US military.
The two American officers were fired upon at close range by an unknown shooter who was able to gain access deep inside the heavily fortified interior ministry.
The Pentagon said Mr Panetta spoke by phone with his Afghan counterpart, Defense Minister Abdul Rahim Wardak, who apologised over the incident.
In the conversation, Mr Panetta urged Mr Wardak to take steps to protect foreign forces.
"Minister Wardak said that President (Hamid) Karzai was assembling the religious leaders, parliamentarians, justices of the Supreme Court, and other senior Afghan officials to take urgent steps to do so (curtail violence)," said George Little, a Pentagon spokesman.
In Kabul, General John Allen, the top US and NATO commander in Afghanistan, met with Afghan Interior Minister Bismillah Mohammadi, who offered both his condolences to the families and his apologies, the Pentagon said.
"The (Interior) Minister pledged his complete cooperation in investigating today's tragedy and in taking stronger measures to protect ISAF personnel," Mr Little said, referring to the International Security Assistance Force.
The Taliban has claimed it was responsible for the killings.
The Taliban said in a statement on itswebsite that "a hero mujahid Abdul Rahman" killed four advisors over the burning of Korans at a US-run military base. However, government sources say two advisors were killed in the incident.
