A roadside bomb attack has killed at least six children, including four girls, attending a wedding in Helmand province of Afghanistan, officials have said.

The children, aged between seven and 12, died when the bomb detonated as they collected water from a river during celebrations on Thursday, provincial administration spokesman Omar Zwak told AFP news agency.

Zwak blamed the attack on Taliban rebels intending to target government employees at the event.

"The Taliban may have planted the bomb to hit local government staff who were at the wedding, but it killed innocent children" Zwak said.

Taliban rebels regularly use roadside bombs to target government officials, and NATO and Afghan soldiers, but civilians and children are also often killed and wounded by the attacks.

According to UN statistics, civilian deaths rose by 24 percent in the first half of 2013 compared to last year.

The UN registered 2,499 civilian casualties between January and June, attributing 74 percent to anti-government forces and nine percent to pro-government forces.

Children accounted for 21 per cent of all civilians killed and wounded and casualties caused by IEDs - the Taliban's weapon of choice - had risen 41 per cent, it said.

Source: Agencies