Kandahar: A remote-controlled bomb exploded near families having a picnic in southern Afghanistan on Wednesday, killing at least 13 people and wounding about 40, Nato and Afghan officials said.

Afghan officials said the attack took place in a village near Lashkar Gah, capital of Helmand province, as farmers were receiving seeds being handed out to persuade Afghans to abandon the poppy crops that produce heroin.

A Nato official said at least 13 people were killed and dozens more wounded.

The bomb was probably a Taliban-style crudely-made improvised explosive device, said the official with Nato's International Security Assistance Force.

"We don't know the exact cause, but it was likely to be an IED," he said on condition of anonymity.

ISAF helicopters evacuated 40 people to nearby hospitals, he said, adding 32 were in serious condition.

Afghanistan's interior ministry said the bomb was attached to a bicycle and detonated by remote control.

Helmand province is a volatile vortex of the insurgency that has been blighting Afghanistan for more than eight years, with Taliban working with drug gangs to keep much of the region out of the writ of the Afghan government.