|Afghanistan's security situation remains unstable, as the country enters the summer fighting season [Reuters]
At least 14 civilians, including women and children, have been killed in a NATO air raid in the Afghan southern province of Helmand, local authorities say.
US Marines in Helmand's Nawzad district called in air support after their base came under attack from small arms fire, the provincial government said in a statement.
"During the air strike, two civilian houses were targeted, which killed 14 civilians and six others were wounded," it said.
The statement said the dead included five girls, seven boys and two women.
"ISAF are aware of the reports that civilians were allegedly killed in an ISAF air strike," Major Tim James, a spokesman for the NATO-led International Security Assistance Force, told the AFP news agency.
Aslam, a local elder of Nawzad district, said he "lost 12 relatives while 10 others including children were injured" in the air strike.
He said some shots were fired at ISAF helicopters which flew into the area, adding that the choppers returned after 10 to 20 minutes and fired rockets, killing the "innocent civilians".
Afghan authorities said on Sunday NATO had killed 52 people, mostly civilians, in air strikes against fighters, as violence picked up in recent weeks with the start of the fighting season.
Separately, the governor of Nuristan on Sunday said that 18 civilians and 20 police were killed by "friendly fire" during recent US-led air strikes against al-Qaeda-linked fighters in his troubled northeastern province.
Owen Leitch reports on the blast that killed northern Afghanistan's top security chief on Saturday.
Nuristan was the scene of heavy battles last week between the Taliban and Afghan security forces.
The police and civilians were targeted on Wednesday after they were mistaken for al-Qaeda-linked fighters, Jamaluddin Badr said.
"The policemen were killed due to friendly fire," Badr said, adding the air strike in the troubled district of Do Ab targeted a location that the officers had just taken from the fighters during clashes.
"Civilians were killed because the Taliban ... [who] ran out of ammunition fled into the civilians' houses and then the civilians were mistaken with the Taliban and fired upon," the governor said.
Major James of ISAF said those allegations were also being investigated.
"ISAF has sent a fact-finding team to investigate the allegations about civilian and police casualties in Nuristan," he said.
"Our initial reporting does not indicate civilian casualties in that air strike," he added.
Civilian casualties in the US-led war against al-Qaeda-linked Taliban fighters is a sensitive issue and one of the main causes of a widening drift between President Hamid Karzai and his US backers.
Karzai on Saturday ordered his defence minister, Abdul Rahim Wardak, to take over control of night raids from the NATO forces.
Karzai's administration says most civilian casualties occur during such operations and that night raids of civilian homes drive war-weary Afghans against his already-fragile administration.
There are about 130,000 NATO-led foreign troops in Afghanistan, fighting a Taliban-led insurgency launched after the 2001 invasion brought down their regime in Kabul.