Updated

An official says three children and their father died when their car hit a bomb on a road in western Afghanistan, the latest deaths in a sharp rise in civilian casualties.

Farah province spokesman Abdul Rahman Zhawandai says the family was driving early Tuesday when their car hit the buried bomb. The father and children were killed instantly. The mother was critically injured.

Civilian casualties have soared in recent weeks as insurgents attack around the country to test the Afghan security forces, now that international troops have stepped back.

The United Nations says that in just two weeks, violence has killed or wounded 412 civilians, up 24 percent over the same time last year. The U.N. blames insurgents for 84 percent of those deaths.