Gunmen in Afghan uniform kill US soldier

The exit of Defense Minister Abdul Rahim Wardak leaves a vacancy at the helm of the ministry that has overseen rapid expansion of the nation's army. Afghan soldiers are increasingly taking their positions on the front lines of the war as foreign combat troops withdraw.

NATO's goal is to turn over security responsibility to local forces by the end of 2014.

Wardak's resignation comes at the peak of the summer fighting season. Violence on Tuesday hit eastern and southern Afghanistan, where militants have their deepest roots.

The two gunmen wearing Afghan National Army uniforms fired on NATO troops at a base in Paktia province of eastern Afghanistan, killing a soldier, according to the U.S.-led coalition and Afghan officials.

The Taliban claimed responsibility for the shooting, the latest in a rising number of so-called "green-on-blue" attacks in which Afghan security forces, or insurgents disguised in their uniforms, kill their U.S. or NATO partners.

The international military coalition did not disclose the nationality of the service member killed, but a U.S. official said he was American.

A second American official said two U.S. service members were wounded.

The officials spoke on condition of anonymity because they were not authorized to disclose the information to reporters.

So far this year, 27 coalition troops have been killed in 20 such attacks, according to an Associated Press tally. That compares with 11 fatal attacks and 20 deaths the previous year. In 2007 and 2008 there was a combined total of four attacks and four deaths.

Overall this year, 272 U.S. and NATO troops have died in Afghanistan.

Taliban spokesman Zabiullah Mujahid said in a statement that one Afghan soldier killed nine U.S. troops. The Taliban often exaggerate the death tolls from their attacks.

"The soldier who opened fire on the Americans had long been in contact with Taliban in the area," Mujahid said. "The soldier has escaped and has joined the Taliban."

The second U.S. official said both of the gunmen in Afghan army uniforms were in custody.

The Taliban also claimed responsibility for Tuesday's midmorning blast at a NATO base in Logar province, southeast of Kabul.

A suicide attacker, who placed explosives under a load of gravel, drove a pickup truck into a gate of the base near Logar's capital of Pul-i-Alam, provincial police chief Ghulam Sakhi Roogh Lawanay said. At least 11 Afghan civilians were wounded, he said.