Militants attacked U.S. troops patrolling in southeastern Afghanistan (search) on Monday, killing one American soldier and wounding two with gunfire and rockets, the military said.

In other violence Monday, Afghan soldiers clashed with police in the southern Zabul province (search) and Afghan troops battled militiamen in the city of Kandahar (search), killing two, according to local officials.

The American patrol came under fire near Orgun, a town in Paktika province (search) where U.S. troops man a base close to the Pakistani border, spokesman Maj. Mark McCann said.

The two wounded soldiers were rushed to a medical facility at another base in neighboring Khost province, where they were in stable condition, McCann said.

"The patrol received small arms fire and RPG fire," McCann said. "Unfortunately, one U.S. soldier was killed and two wounded."

None of the soldiers was identified.

In Zabul province, Afghan soldiers exchanged fire with police, leaving several casualties and prompting U.S. forces to step in to restore order, police and witnesses said.

The 90-minute gun battle started after Afghan National Army troops disarmed police at a checkpoint and a bazaar in Qalat, the provincial capital, said deputy police chief, Jailani Khan.

He insisted the army had no authority to disarm the police. The fighting subsided after U.S. forces arrived and took over security. He said there were some casualties, but he didn't know how many.

A shopkeeper who was reached by telephone from Kandahar said on condition of anonymity that he saw at least three bodies.

American helicopters were still circling above the city.

U.S. military spokesman confirmed there had been an incident in Qalat, but gave no details. Afghan army officials were not immediately available to comment.

Zabul is one of the most insecure provinces in the lawless reaches of southern and eastern Afghanistan, and has also been scene of heavy fighting in the past year between coalition forces and Taliban rebels.

The United States is helping to train the new national army, which is meant to gradually replace militia security forces usually loyal to local commanders.

In a third incident Monday, Afghan army soldiers opened fire on provincial militiamen in the area of the Durai bazaar in Kandahar city, killing two of them and wounding one, said Khalid Pashtun, spokesman for the Kandahar governor.

He said the circumstances of the clash were still unclear and an investigation was under way.

Also, an ammunition depot at a compound used by Afghan army and U.S. special forces in the city exploded late Sunday, wounding three Afghan soldiers, Pashtun said.

It wasn't clear what caused the blast. No U.S. personnel were reported hurt.

Before the fall of the Taliban (search) regime in late 2001, the compound was used by the hardline regime's leader, Mullah Omar (search).

The latest violence brought to at least 109 the number of U.S. soldiers killed in and around Afghanistan since the launch of Operation Enduring Freedom (search) after the Sept. 11, 2001 attacks.

Fifty-eight of the Americans were killed in action, according to a tally on the Web site of the U.S. Department of Defense, while the rest died in accidents.

Most recently, Cpl. Billy Gomez died last Wednesday of injuries from an Oct. 20 bomb attack on his vehicle in the same province as Monday's assault.

An airmen was killed Oct. 20 when his helicopter crashed in western Afghanistan on a mission to evacuate an injured election worker. The military said a technical problem brought down the aircraft.