The incident happened a day before Afghans go to the polls to directly elect a president for only the second time in their history.

Taliban have warned they will disrupt the polls, raising concerns in the war-weary country that the elections would be overshadowed by violence.

On Tuesday a suicide bomber targeted NATO forces in the eastern part of Kabul, killing 10 people including seven civilians, two UN workers and a NATO soldier, and wounding more than 50 others.

Also Tuesday another bomber attacked an army checkpoint in the southern province of Uruzgan, killing five people.