Suspected insurgents have shot and killed four civilians just outside the Afghan capital.

A provincial spokesman says the four were kidnapped Tuesday as they were traveling from Kabul to a remote area in Wardak province.

He says their bullet-riddled bodies were later found in the Jalrez district.

It was the second such incident in the area in recent weeks. Four Afghan security guards were pulled out of a vehicle and found shot dead in late July.

Civilians are increasingly bearing the brunt of the Afghan war, with civilian casualties on the rise for five consecutive years. A United Nations report released earlier this year found that more than 3,000 civilians were killed in 2011 — an eight percent increase from the previous year.

Also Wednesday, NATO said bomb attacks killed three of its service members. Two coalition soldiers and a local Afghan interpreter were killed in the east, while one service member was killed in the south. No other details were given.