Officials say at least 18 people have been killed in three separate attacks in Afghanistan.

Police said 10 civilians, including women and a child, were killed when their vehicle hit a roadside bomb on its way to a wedding in southern Helmand province.

In eastern Laghman province, an army convoy struck a landmine. Five soldiers were killed in the incident near the provincial capital, Mehtarlam.

Three police officers were killed when a suicide bomber detonated his explosives-laden motorbike at a police checkpoint in Kandahar city.

The attacks came as Afghan forces take increasing responsibility for the country's security as international forces prepare to leave by the end of 2014.