KABUL - A blast outside a U.S. base in eastern Afghanistan killed two American troops and wounded four others Saturday, a military spokesman said.
The troops were attacked outside the base in eastern Paktika province, but there were no immediate details about the nature of the blast, said Tech. Sgt. Chuck Marsh, a U.S. military spokesman.
Insurgents also attacked the base with small arms fire before U.S. troops called in airstrikes on their positions, Marsh said.
The deaths came as thousands of Marines in southern Afghanistan pursued the biggest U.S. military operation here since the American-led invasion of 2001, trying to cut insurgent supply lines and win over local elders.
Saturday's attack happened near an area in eastern Paktika province where an American soldier and three Afghans with him were believed captured by insurgents Tuesday.
U.S. troops continued looking for the soldier, Navy Chief Petty Officer Brian Naranjo said Friday. The military has not publicly identified him.
No immediate claim of responsibility was made by any insurgent group for the missing soldier or Saturday's attack.
Much of the area bordering Pakistan is controlled by the Taliban faction led by Sirajuddin Haqqani, whom the U.S. has accused of masterminding beheadings and suicide bombings, including the July 2008 attack on the Indian Embassy in Kabul that killed 60 people.
The Taliban, who have made a violent comeback following their initial defeat in the 2001 U.S. invasion, have stepped up attacks in former strongholds of eastern and southern Afghanistan.
Responding to the deteriorating security situation, President Barack Obama's administration has ordered 21,000 additional troops to Afghanistan and expects the total number of U.S. forces there to reach 68,000 by year's end.
That is double the number of troops in Afghanistan in 2008 but still half as many as are now in Iraq.