An Afghan security man stands guard on the roof of a damaged house following a gun battle between militants and Afghan security forces on the outskirts of Kabul, Afghanistan, Thursday, Aug. 2, 2012.

HEIDI VOGT and MIRWAIS KHAN

KABUL, Afghanistan (AP) - Insurgents attacked a large party in a Taliban-controlled area of southern Afghanistan and beheaded 17 people, officials said on Monday.

The head of the local government initially said the victims were civilians at a celebration late Sunday involving music and dancing in the Musa Qala district of Helmand province. The official, Neyamatullah Khan, said the Taliban killed the party-goers for flouting the extreme brand of Islam embraced by the militants.

However, a provincial government official said later that those killed were caught up in a fight between two Taliban commanders over two women, who were among the dead. Daoud Ahmadi, a spokesman for the provincial government, said shooting broke out during the fight. He said it was unclear whether the music and dancing triggered the violence and whether the dead were all civilians or possibly included some fighters.

Ahmadi said all of the bodies were decapitated but it was not clear if they had been shot first.

In other violence, two American soldiers were shot and killed by one of their Afghan colleagues in the east, military officials said. Afghan officials said the killings appeared to be accidental, however NATO would not comment on the question of whether the killings were intentional or accidental.

The Taliban has controlled large parts of the district of Musa Qala, an area encompassing more than 100 villages, since 2001. They enforce the same strict interpretation of Islamic law that was imposed on all of Afghanistan during Taliban rule of Afghanistan from 1996-2001.

U.S. Marines have battled the Taliban for years in Musa Qala, but the insurgent group still wields in significant power in the area as international forces across the country draw down and hand over control to Afghan forces. Helmand province, where Musa Qala is located, is one of the areas seeing the largest reduction in U.S. troops. The U.S. started reducing forces from a peak of nearly 103,000 last year, and plans to have 68,000 troops by October.

Many Afghans and international observers have expressed concerns that the Taliban will try to re-impose strict Islamic justice as international forces withdraw. Under the Taliban, all music and film was banned as un-Islamic, and women were barred from leaving their homes without a male family member as an escort.

The Taliban spokesman for southern Afghanistan could not be reached for comment on the beheadings.

As the drawdown progresses, there has been a surge in attacks by Afghan forces against their international allies.

A group of U.S. and Afghan soldiers came under an insurgent attack in Laghman province on Monday, said Noman Hatefi, a spokesman for the Afghan army corps in eastern Afghanistan. He said the troops returned fire and ran to take up fighting positions.

He claimed the two Americans were killed when an Afghan soldier fell and accidentally discharged his weapon.

"He didn't do this intentionally. But then the commander of the (Afghan) unit started shouting at him" 'What did you do? You killed two NATO soldiers!' And so he threw down his weapon and started to run," Hatefi said.

The American troops had already called in air support to help with the insurgent attack and the aircraft fired on the escaping soldier from above, killing him, Hatefi said.

NATO spokesman Lt. Col. Hagen Messer of Germany confirmed that two international soldiers were killed by an Afghan soldier in Laghman province, but would not comment on whether the killing was intentional or accidental.

Insider attacks have been a problem for the U.S.-led military coalition for years, but it has exploded recently into a crisis. There have been at least 33 such attacks so far this year, killing 42 coalition members, mostly Americans. Last year there were 21 attacks, killing 35; and in 2010 there were 11 attacks with 20 deaths. The latest killings brought the number of Americans killed by allied forces this month to 12.

The chief spokesman for NATO forces in the country said coalition forces were not pulling back from collaborating with the Afghans because of the attacks.

"We are not going to reduce the close relationship with our Afghan partners," Brig. Gen. Gunter Katz told reporters in the capital.

Taliban spokesman Zabiullah Mujahid said that he could not confirm any link between the attacker in Monday's shooting and the insurgency. In previous insider attacks, the Taliban have quickly claimed responsibility and named the assailants.

Helmand officials also reported that 10 Afghan soldiers were killed in an attack on a checkpoint in the south, and five were either kidnapped or joined their assailants. Ahmadi, the provincial spokesman, said insurgents attacked the checkpoint in Washir district Sunday evening. Four soldiers were wounded he said. The Afghan Defense Ministry said the checkpoint was attacked by more than 100 insurgents.

Ahmadi said the five missing soldiers left with the insurgents but it was unclear if they were kidnapped or went voluntarily.