Officials say a motorcycle bomb has exploded in southern Afghanistan, killing an Afghan soldier and a civilian.

Local police chief Ghulam Ali says Wednesday's blast near a market in Helmand province's heavily contested Sangin district also left 15 people wounded.

Helmand government spokesman Omar Zwak says the explosives in a parked motorcycle were remotely detonated as an army and police patrol passed by.

Ali said three soldiers, one local police officer and 11 civilians were among the wounded.

Taliban insurgents have unleashed a fierce wave of attacks on Afghan security forces and government targets in recent weeks.

The offensive has pushed violence to some of the highest levels of the 12-year war as Afghan forces take over most security responsibility from international troops set to withdraw next year.