The blast happened in the southern city of Kandahar on Monday, leaving five people dead and six others injured.
The three bombers and two children walking by were killed instantly in the explosion.
According to local police officials, the incident took place when an explosive-packed car accidently detonated before it reached its intended target which was the local market.
Insecurity continues to rise across Afghanistan, despite the presence of thousands of US-led forces in the war-torn country.
Washington invaded Afghanistan in 2001 under the pretext of combating terrorism and toppling the Taliban regime.
The US-led war in Afghanistan, with civilian and military casualties at record highs, has become the longest military conflict in the American history.
AZA/TNP/JR/AZ