US Secretary of State Hillary Clinton voiced doubt Friday that France would accelerate its troop pullout from Afghanistan, after four French troops were killed by an Afghan soldier.
But the Pentagon said it was up to Paris whether to bring its forces home from Afghanistan early, as Clinton and other US officials offered condolences to the loved ones of the soldiers killed.
"I'm in great sympathy with what happened to the French soldiers. It was terrible and I can certainly appreciate the strong feelings that are being expressed," the chief US diplomat said at a press conference.
The United States offered "our deepest condolences," she said.
"We are in close contact with our French colleagues and we have no reason to believe that France will do anything other than continue to be part of the very carefully considered transition process as we look at our exit as previously agreed upon in Lisbon," Clinton added.
In Lisbon, on November 20, 2010, Nato leaders endorsed a plan for their soldiers to start handing security responsibilities to Afghan forces, with the aim of ceding full control by the end of 2014.
French President Nicolas Sarkozy warned Friday he may accelerate the withdrawal of France's 3,600 troops from Afghanistan after an Afghan soldier shot dead four unarmed French troops during a sports session inside a base.
Sarkozy suspended French military training and joint combat operations with Afghan troops, and sent Defense Minister Gerard Longuet to probe the attack in which at least 15 French soldiers were also wounded, eight seriously.
At the Pentagon, Navy Captain John Kirby said: "We mourn for their losses today, but those are decisions that only the French government and the French people can make."
"Their contributions are theirs to determine and theirs to amend as they see fit," Kirby said, calling the French "great allies and great friends."
White House spokesman Jay Carney said French forces had served with "valor and honor" in Afghanistan, but did not comment on the French leader's remarks.
State Department spokeswoman Victoria Nuland said Wendy Sherman, the under secretary for political affairs, had discussed the incident in Washington with her French counterpart Jacques Audibert.
Deployed mainly in the provinces of Kabul and Kapisa, the scene of Friday's shooting, the French forces are currently scheduled to be withdrawn by the end of 2013.
The incident was the latest in a string of attacks by allied Afghan forces on US and Nato soldiers, which a classified report leaked to the New York Times said reflected a "systemic" problem and not just isolated incidents.
Between May 2007 and May 2011, at least 58 US and Nato personnel were killed in 26 attacks by Afghan soldiers and the police, the classified 70-page report said, according to The Times.
It includes an April 2011 incident in which an Afghan Air Force colonel killed eight US officers and a contractor with shots to the head inside their headquarters.
"We believe that they do appear to be increasing in frequency in recent months. What we can't discern is a cause for that," said Kirby.
"We're certainly concerned about these incidents and ISAF officials are taking a look at it. But we also don't believe that this is an endemic or systemic problem. The great majority of partnered operations, and frankly most of our operations are partnered, are done successfully, smoothly, efficiently," he said.
The report emphasizes the killings are the result of a decade of contempt that each side has for each other, and profound ill will among both civilians and militaries on both sides. It downplayed the role of Taliban infiltrators in the incidents.
"Lethal altercations are clearly not rare or isolated; they reflect a rapidly growing systemic homicide threat (a magnitude of which may be unprecedented between 'allies' in modern military history)," the report said, according to The Times.
Official Nato statements downplaying the incidents "seem disingenuous, if not profoundly intellectually dishonest," said the report.