U.S. warplanes helped Afghan forces pound Taliban militants in the mountains of southern Afghanistan Tuesday, killing some 20 suspected insurgents at a recently discovered camp, a senior Afghan commander said.

The three-hour battle occurred in Arghistan district of Kandahar province (search), some 120 miles southwest of the capital, Kabul, provincial military commander Khan Mohammed told The Associated Press.

Khan said about 150 Afghan troops attacked the camp in an area called Ghbragyan on Tuesday afternoon, sparking a three-hour gunbattle in which three of his soldiers were injured.

"After that, U.S. warplanes came and started bombing the Taliban area," Khan said. "U.S. forces told us that they had seen the bodies of about 20 dead Taliban."

Khan said he didn't know how many Taliban were using the camp on a rough mountainside, and U.S. military officials in Kabul had no immediate comment.

U.S. military spokeswoman Master Sgt. Cindy Beam said Wednesday that "ground troops did call in air support last night," and said more details would be released later.

Still, the clash appeared the most deadly since U.S.-led forces and insurgents stepped up operations in the spring, fueling a spiral of violence that has killed more than 350 people this year, casting a shadow over plans for national elections in September.

Some 20,000 U.S. troops are in Afghanistan, including some 2,000 extra Marines stationed in the south of the country. The U.S. force is at its largest since the Taliban government was ousted in 2001 for harboring Usama bin Laden.

The top U.S. general here has vowed to crush anti-government militants, which also include followers of fugitive warlord Gulbuddin Hekmatyar (search), this year with a combination of military might and reconstruction aid to persuade ordinary Afghans to turn their back on the militants and back the faltering peace process.

Elsewhere, officials in the embattled south and east said Taliban militants riding motorcycles killed an Afghan soldier in an attack on troops guarding a shipment of aid, while a rocket attack further west killed two people.

Militia ambushed the convoy carrying tractors and generators Saturday as it drove toward Waza Khwa, a remote town in Paktika province (search), about 170 miles southwest of Kabul, provincial police chief Abdul Rahim Khan said.

A second soldier was wounded, the police chief said.

He said the assailants — about 20 men on motorbikes — retreated after a 30-minute gunbattle.

The four tractors and five generators, paid for by aid groups as part of efforts to re-establish local government in the lawless province, were undamaged.

Abdul Hakim Latifi, who claims to speak for the Taliban, said two of its fighters were injured in the shooting.

Latifi said two more Afghan soldiers were killed Sunday night in a rocket attack near Tirin Kot, the capital of Uruzgan province, about 250 miles southwest of Kabul. But Uruzgan police chief Rozi Khan said the victims were civilians.

A Norwegian peacekeeper died Sunday in a rocket attack in Kabul also claimed by Latifi for the Taliban.