Seventeen civilians, including women, are killed by the Taliban in southern Afghanistan, according to a local official.
The bodies were found on Monday in a house near the Musa Qala district where a party was held on Sunday night with music and mixed-sex dancing, said district governor Nimatullah.
There were early unconfirmed reports that the victims, including two women, had been beheaded.
Men and women do not usually mingle in Afghanistan unless they are related, and parties involving both genders are rare and kept secret.
The killings, about 46 miles north of the provincial capital Lashkar Gah, came at the beginning of a violent 24 hours for Nato and Afghan authorities in which 10 Afghan soldiers were killed in a mass insurgent attack, also in Helmand, while two US soldiers were slain by a rogue Afghan soldier.
“The victims threw a late-night dance and music party when the Taliban attacked” on Sunday night, Nimatullah, who only has one name, told Reuters.
There were no immediate claims of responsibility.
During their five-year reign, which was toppled by US-backed Afghan forces, sparking the present Nato-led war, the Taliban banned women from voting, most work and leaving their homes unaccompanied by their husband or a male relative.
Though those rights have been regained, Afghanistan remains one of the worst places on earth to be a woman.
In another setback for Nato, an Afghan soldier shot dead two US troops in east Afghanistan on Monday, the latest in a series of insider killings that have strained trust between the allies ahead of a 2014 handover to Afghan security forces.
The deaths in Laghman province brought to 12 the number of foreign soldiers killed this month, prompting Nato to increase security against insider attacks, including requiring soldiers to carry loaded weapons at all times on base.
US Joint Chiefs of Staff chairman Martin Dempsey visited Kabul last week to talk about rogue shootings and urge Afghan officials to take tougher preventative action.
“Isaf troops returned fire, killing the ANA (Afghan National Army) soldier who committed the attack,” the Nato-led International Security Assistance Force said in a statement.
There have been 33 insider attacks so far this year that have led to 42 coalition deaths. That is a sharp increase from 2011, when, during the whole year, 35 coalition troops were killed in such attacks, 24 of whom were American.
The chief coalition spokesman, German Brigadier-General Gunter Katz, told reporters the shootings would not prompt a winding back of vital cooperation or training with Afghan police and soldiers to curtail more shootings.
“We are not going to reduce the close relationship with our Afghan partners,” Katz said.