At least four civilians were killed and two others were injured in a bomb blast in the southern Helmand province Monday morning, locals officials said.
The incident happened at about 09:00 am local time in Marja district when the vehicle they were traveling in hit a roadside bomb, provincial police chief Abdul Nabi Elham said.
The injured were taken to a nearby hospital; all the victims are civilians, he said.
No group, including the Taliban, has claimed responsibility for the blast. Insurgents use improvised explosive devices to target Afghan and Nato troops, but most of the victims are civilians who are unwittingly caught in the blast.
The UN recently released a report stating that the number of civilians killed in Afghanistan has dropped for the first time in six years, but the number of injured has increased.
The UN documented 2,754 civilian deaths in 2012, a 12 percent drop, and 4,805 injuries, a slight rise. In total, 81 percent of civilian casualties in 2012 were attributed to militants, while 8 percent resulted from operations by pro-government forces. Over the past six years, 14,728 Afghans have been killed in the war.
The reduction in civilian casualties in 2012 was attributed to less fighting on the ground and a decline in suicide attacks and air operations. But the report also expressed concern about the re-emergence of armed groups, particularly in Afghanistan's north.
The US report also warned that civilians are facing an increase in threats, intimidation and interference in their rights to education, health, justice and freedom of movement from militants.