Officials said on Friday that Afghan soldiers were being blamed for firing mortars at a wedding party that killed 17 women and children

Officials said on Friday that Afghan soldiers were being blamed for firing mortars at a wedding party that killed 17 women and children, in a mistaken strike that overshadowed the transfer of nationwide security from NATO forces.

The deaths on Wednesday evening in the southern province of Helmand came on the eve of a ceremony in Kabul when President Ashraf Ghani congratulated the Afghan army and police for taking over from NATO forces who have ended their combat mission.

"The troops fired mortar rounds on a wedding ceremony after the militants in the same area attacked an army checkpoint," Mohammad Jan Rasoulyar, deputy governor of Helmand, told AFP.

"Those Afghan army troops accused of firing the mortar rounds have been referred to a military court."

Four soldiers, including one commander, were arrested and taken to the provincial capital Lashkar Gah.

Officials said that a delegation sent to restive Sangin district in Helmand, where the incident took place, had been told that at least two rockets were fired at the wedding ceremony from different army outposts.

Some witnesses said the army attack was triggered when wedding guests shot celebratory gunfire into the air as the bride was brought to the groom's house.

A room where female guests had gathered was hit, with 17 women and children killed and 49 other people wounded. Officials had earlier reported the mortars killed at least 20 guests, but Rasoulyar said the toll had been revised down.

"Eyewitnesses told the delegation that militants had earlier attacked a security checkpoint in the area," Helmand police spokesman Farid Obaid told AFP.

"Then the Afghan army troops attacked with mortar rounds that landed on the wedding