In a separate incident in western Ghor province, a clash on Sunday between poppy farmers and police involved in eradication left one civilian dead and two wounded.
Some 500 people had gathered to protest against government attempts to destroy the crop, following last year's record harvest.
In 2006, poppy production in the country rose 49 per cent to 6,700 tonnes, enough to make about 670 tonness of heroin.
The Afghan government has rejected US offers to spray the fields with herbicides and pledged it would step up poppy eradication using tractors and manpower.
In southern Afghanistan, suspected Taliban fighters have fired a rocket at a Canadian military armoured vehicle in the city of Kandahar on Sunday.
Alex Watsen, an army spokesman, said the Canadians fired back, killing one suspected fighter, but that no troops were injured.
Watsen said one policeman was also killed in the ensuing gunfight.