Taliban Islamist insurgents beheaded 17 party-goers, 10 Afghan soldiers were killed and two NATO troops shot dead in a new insider attack in a bloody day across Afghanistan, officials said Monday.

The party-goers, including two women, were holding a gathering with music in a southern Afghanistan village.

"I can confirm that this is the work of the Taliban," the Helmand provincial governor's spokesman Daud Ahmadi told AFP. "Two women and 15 men were beheaded. They were partying with music in an area under the control of the Taliban."

The hardliners were notorious during their rule for public executions and the suppression of music and parties.

Nematullah Khan, the Musa Qala district chief, confirmed that the villagers had organised a party with music, and a local official said he suspected that the two women had been dancing.

Secret parties with dancing women from a gypsy-type tribe are common across southern Afghanistan.

During their 1996-2001 rule in Afghanistan the Taliban, now waging a fierce insurgency against the NATO-backed government of President Hamid Karzai, also tried to stop the mixing of men and women who were not related.

"This callous act clearly demonstrates the insurgents' willingness to stop at nothing in terrorising civilians," said General John Allen, commander of NATO'S International Security Assistance Force.

He pledged the assistance of NATO troops "to help bring these criminals to swift and sure justice", while the US embassy in Kabul condemned the killings as "a shameful act".

The UN mission in Afghanistan said: "This criminal act is unjustifiable and totally disregards the sanctity of human life.

"UNAMA has repeatedly stated that the killing of civilians is a clear violation of international humanitarian and human rights laws and has called for the perpetrators of such reprehensible acts to be brought to justice."

Britain too joined in condemning the killings "in the strongest terms".

Foreign Office Minister Alistair Burt said: "I am appalled at the cruel killing of 17 people at a party.... The facts are still being established but early indications are that the Taliban were responsible."

The insurgents have in the past been blamed for beheading local villagers, mostly over charges of spying for Afghan and US-led NATO forces.

Haji Musa Khan, a tribal elder in Musa Qala district, said the region had seen a surge in such killings in recent months.

"We had three people beheaded during the month of Ramadan. Another person, the son of a tribal elder, was beheaded recently," he said.

Khan said the killings followed major military operations by Afghan and NATO troops in the area.

-- After beheadings, Taliban strike army --

Hours after the beheadings, Taliban insurgents overran an Afghan army post in the same province in a pre-dawn attack on Monday, killing 10 troops, authorities said.

Four soldiers were wounded and six others were missing following the attack in Helmand's Washir district, senior regional police officer Colonel Mohammad Ismael Hotak told AFP.

Helmand spokesman Ahmadi confirmed the incident and said the attack was an "insider plot" in which some army soldiers helped the rebels attack the post.

If it is confirmed that the attack was facilitated by soldiers it will mark a new escalation in a string of insider attacks on Afghan and NATO security forces.

Two NATO soldiers were also killed Monday when an Afghan army soldier turned his weapon against them in a "green-on-blue" attack in eastern Laghman province, the US-led International Security Assistance Force (ISAF) said.

"ISAF soldiers returned fire and killed the attacker," ISAF said.

The latest NATO deaths take the toll from insider attacks this month alone to 12 and to a total of 42 this year, making up around 13 percent of all NATO deaths in 2012.

NATO, which has about 130,000 troops in Afghanistan, has struggled to stem the attacks and they have become a major issue in the Afghan war, eroding trust between the two forces.

Taliban insurgents claim responsibility for many of the attacks, but NATO attributes most to cultural differences, stress and personal animosity between Afghan troops and their international allies.

ISAF spokesman Brigadier General Gunter Katz told reporters Monday that the attacks would not lead to less cooperation with Afghan troops as NATO prepares to pull out from the war in 2014.

"Let me clearly say, we are not going to reduce the close relationship with our Afghan partners. We assess that closer cooperation results in stronger bonds and increasing trust and friendship," he said.

"These incidents will not affect our operation. The campaign is on track, we effectively fight the insurgency and most importantly we continue to fight alongside our partners from the Afghan security forces."