Kabul: Afghan authorities on Wednesday accused NATO troops of killing four policemen by accident in one of the most dangerous Taliban strongholds in the south.
Police and the interior ministry said the policemen were "mistakenly" killed following an exchange of fire in Kandahar province.
NATO troops "mistakenly attacked a police post in Kandahar province`s Arghandab district. Four police were martyred in the clash," the ministry said in a statement. Two others were injured, it added.
A spokesman for NATO`s US-led International Security Assistance Force (ISAF) in the Afghan capital Kabul said the military was looking in
Kandahar provincial police chief Abdul Raziq confirmed the incident.
"They were mistaken for insurgents," Raziq said. "The police returned fire and there was a brief exchange of fire."
He said initially that two officers died, but later doubled the death toll.
Afghan officials said the officers were members of the regular police force, although Raziq said earlier they were members of a local anti-Taliban initiative in which people are recruited to protect their own villages.
Faiz Mohammad, who worked alongside the dead men, said they were praying when they came under fire from foreign forces. He added that four other people were wounded and evacuated by ISAF for treatment.
Like Muslims across the world, Afghans are currently observing the holy month of Ramadan in which faithful fast from dawn to dusk.
An ISAF spokesman said it was investigating the incident.
"We`re aware of an incident in Kandahar province. A joint Afghan and ISAF investigation is underway. We`re investigating this," a spokesman said.
The Afghan government has frequently criticised NATO troops over friendly fire incidents and operations in which civilians are killed.
In late May, President Hamid Karzai issued his "last warning" to the US military to avoid "arbitrary" operations that kill Afghan civilians, saying such incidents were tantamount to "murder".
There are around 140,000 international forces in Afghanistan fighting the Taliban and other insurgents, alongside Afghan government forces. Around 100,000 of them are American.
Some troop withdrawals have already started as part of a drawdown, which should see all foreign combat forces leave Afghanistan by the end of 2014 but analysts question the ability of Afghan forces to fight the insurgency.
Kandahar is considered the birthplace of the Taliban.