KABUL — Taliban militants fired rockets and mortars at a U.S. base in eastern Afghanistan on Saturday, killing two American soldiers in a fierce battle as thousands of Marines in the south continued with their massive anti-Taliban push.

The multi-pronged attack in eastern Paktika province — where an American soldier was captured this week — included a truck bombing near the camp's gates. The battle ended only after U.S. forces called in airstrikes on militants.

The battle near the Pakistan border is hundreds of miles (kilometers) from the massive Marine assault in southern Helmand province. It underscores the militants' ability to inflict casualties on the over-stretched U.S. forces as they widen their battle against the Taliban, who have made a violent comeback following their initial defeat in the American-led 2001 invasion.

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.

As part of the new strategy, 4,000 Marines poured into volatile Helmand province on Thursday in the biggest U.S. military operation in Afghanistan since 2001, trying to cut insurgent supply lines and win over local elders.

More than 30 insurgents were killed in the Saturday battle in Zerok district of Paktika province, said Hamidullah Zawak, the provincial governor spokesman. Seven American and two Afghan troops were wounded, a U.S. military spokesman said.

Attack helicopters, airstrikes and fire from U.S. troops killed at least 10 militants, according to a statement from the NATO-led force under which these American troops fight. Troops detained one militant, it said. The discrepancy in the militant death tolls could not immediately be reconciled.

During the battle, an insurgent drove a truck filled with explosives and gravel toward the gates of the U.S. base, Zawak said. When the driver did not heed warnings to stop, troops opened fire on the truck, which exploded, he said.

The blast happened as rocket and mortar fire peppered the base, killing two U.S. troops and wounding seven other American soldiers, said Spc. April Campbell, a U.S. military spokeswoman.

The clash lasted for two hours before U.S.-called airstrikes that ended the fight, Zawak said.

Two Afghan soldiers were also wounded. The base housed both U.S. and Afghan soldiers.