Up to 30 Taliban insurgents, including suicide bombers, attacked a U.S. base in Afghanistan's east on Saturday, officials said, but there were no details available about possible casualties or damage.
The attack began overnight at the well-fortified Forward Operating Base Chapman in Khost province near the southeastern border with Pakistan, where U.S. and other foreign forces have been stepping up operations against a resurgent Taliban.
Seven Central Intelligence Agency officers were killed by a suicide bomber inside the base last December, the second-most deadly attack in CIA history.
Lieutenant Commander Katie Kendrick, a spokeswoman for the NATO-led International Security Assistance Force, confirmed the new attack but could give few other details.
"There is ongoing activity there, but it is fresh and I can't give more details," Kendrick said.
Zabihullah Mujahid, a spokesman for the Taliban, said 30 fighters had attacked the base. They included suicide bombers and others armed with rockets and machine guns, Mujahid told Reuters by telephone from an undisclosed location.
Despite the presence of almost 150,000 foreign troops, violence across Afghanistan is at its worst since the Taliban were ousted by U.S.-backed Afghan forces in late 2001.
Taliban-led insurgents have launched increasingly brazen attacks around Afghanistan in a bid to topple the government and force out foreign troops. More than 2,000 foreign troops have been killed, most of them Americans, since the conflict began.
Hundreds of civilians have also been caught in the crossfire, with civilian deaths spiking by 31 percent in the first six months of this year, according to a United Nations report.