Afghan President Hamid Karzai's demand for US special forces to leave a key province came as a surprise to American commanders, who had no advance warning of the order, officials said Monday.
It remained unclear what led Karzai to issue a blunt announcement that US special operations force would have two weeks to withdraw from the strategic Wardak province, southwest of the capital Kabul, two US officials said.
"We're not aware of any incident that would have generated this kind of response," one official, who spoke on condition of anonymity, told AFP.
In his statement Sunday, Karzai charged that Afghans working with US forces had carried out torture and murder that has triggered local outrage.
The Pentagon confirmed that a special panel of Afghan officials and officers from the NATO-led International Security Assistance Fore (ISAF) were looking into Karzai's allegations.
"There has been a joint commission established by ISAF and the government of Afghanistan to look into the issues that surfaced over the weekend," spokesman George Little told reporters.
"We're trying to see clarity from the government of Afghanistan," he added.
Asked if the United States would pull out its elite special operations units from the province, Little said: "It's premature to speculate on what the outcome of what our discussions would be."
Wardak is a deeply troubled flashpoint where a Chinook helicopter was shot down by the Taliban in August 2011, killing eight Afghans and 30 Americans. It was the deadliest single incident for American troops in the entire war.
Karzai has had a troubled relationship with Washington for years and expressed anger in public statements in the past after errant US air strikes killed Afghan civilians.
Analysts said Karzai's move conveyed Kabul's growing distrust of the NATO-led troops and their desire to impose their authority over local militia, who are trained by the Americans but operate without government control in the war against the Taliban.