A U.S. special operations soldier was killed in action in eastern Afghanistan, U.S. military said Friday.

In a neighboring province, meanwhile, coalition troops arrested four people and seized weapons stored in caves by insurgents.

Petty Officer 1st Class David M. Tapper, 32, of Camden County, N.J., died from injuries suffered on Wednesday, the Defense Department said in Washington. The U.S. military's Central Command (search) said his injuries were sustained during a "hostile fire incident" around Orgun in Paktika province.

On Thursday, the military said a coalition soldier had been slightly wounded by a bomb while on patrol in the same region. It was not immediately clear whether the two incidents were linked.

About 11,500 troops of the U.S.-led coalition are in Afghanistan hunting down remnants of the ousted Taliban regime (search) and its allies. In all, 31 U.S. soldiers have been killed in action in Afghanistan, and 162 wounded due to hostilities, the U.S. military said.

Attacks by alleged Taliban have increased, with a string of attacks in the country's south and east, including two deadly raids targeting Afghan police in Paktika last weekend -- reportedly launched by hundreds of guerrillas traveling in pickup trucks from the direction of neighboring Pakistan, a key U.S. ally in the war on terror.

The increased violence comes amid reports that Mullah Mohammed Omar (search), the leader of the Taliban regime ousted in 2001, has reorganized his fighters into regional commands around the country to carry out attacks.

Col. Rodney Davis, spokesman at Bagram Air Base, said Friday that special operations soldiers raided weapons caches used by insurgents in eastern Khost province and arrested four people.

In the raid Wednesday, the coalition seized numerous missiles, small arms ammunition, Russian and Chinese 60 mm mortar rounds, anti-personnel mines, automatic weapons and hand grenades. The weaponry was found stored in two compounds and three caves near the Neka Valley.

"Four persons were taken under control and the ordnance was seized and transported to Khost for destruction at a later date," Davis said in a statement from Bagram, the U.S.-led coalition's headquarters in Afghanistan.