KABUL, April 1, 2008 (AFP) - The NATO force in Afghanistan said Tuesday it killed three insurgents in a late night air strike, but a government official insisted the men were farmers watering their crops.

The strike in the volatile southern province of Kandahar was called in late Monday when the three were spotted placing home-made bombs on a road near an International Security Assistance Force base, ISAF said.

'Being careful to assess the situation, ISAF forces confirmed the intent of the insurgents by conducting further reconnaissance,' it said in a statement.

'ISAF forces engaged the insurgents by calling in close air support, and a precision guided munition was dropped on the insurgents,' it said, adding it had foiled an attempt to kill civilians and soldiers.

The strike was in Panjwayi district, one of the most volatile in Kandahar which has seen regular attacks by Taliban extremists.

The district governor, Shah Baran, insisted that the three were farmers irrigating their land. In some Afghan villages, farmers only have access to a communal water supply at night.

'Our investigations show that they were not planting mines. They were not Taliban, they were farmers who were irrigating their lands at the time of the bombing,' Baran told AFP.

It was impossible to independently verify what had happened, with the area largely off-limits because of the security situation.

Civilian casualties are extremely sensitive in Afghanistan, where about 70,000 international soldiers are fighting alongside Afghan security forces to defeat a Taliban-led insurgency which was at its deadliest last year.

Hundreds of civilians have been killed in the crossfire between security forces and rebels, or in rebels attacks. About 1,500 civilians were killed last year, according to United Nations' data.