Kabul: A roadside bomb killed four civilians in Afghanistan's southern province of Uruzgan on Friday, the provincial head of the crime investigation unit said.

"Four civilians were killed and one injured when their vehicle hit a Taliban-planted mine in Trinkot city on Friday morning," said Gulab Khan.

All the victims were male and the civilian who was injured was in a critical condition, he added.

There was no immediate claim of responsibility for the attack, but roadside bombs are frequently planted by Taliban-led insurgents fighting a decade-long war against NATO-led foreign troops and Afghan government forces.

There are around 130,000 international troops, mainly from the United States, in Afghanistan helping government forces combat the insurgency.

The United Nations said the number of civilians killed in violence in Afghanistan rose by 15 per cent in the first six months of this year to 1,462, with insurgents blamed for 80 percent of the killings.

(Agencies)