Five civilians, including four children, were killed Thursday by a roadside bomb in north-eastern Afghanistan, officials said.

The civilians were killed when a mine exploded in Taqab district of Kapisa province, district governor Abdul Hakim Akhundzada said.

'The explosion killed five civilians, including four children, and injured three children,' NATO said in a statement.

Akhundzada said that the children were between 12 and 15 years old and were playing near a dirt road in the district when the blast occurred. He blamed the Taliban militants for the attack. An adult civilian also died.

'The cowardly act of hiding behind children and in this case killing them is disgraceful,' General Mohammad Zahir Azimi, a defence ministry spokesman, was quoted as saying by the NATO statement.

There were no Afghan or International Security Assistance Force personnel in the area at the time of the blast, the statement said, adding that the wounded children were taken to local military medical facilities for treatment.

More than 2,400 civilians, including around 350 children, were killed in the conflict in Afghanistan last year, according to a United Nations report. Nearly 70 percent of the deaths were caused by the Taliban, and the rest by the NATO-led International Security Assistance Force.