LASHKAR GAH, Afghanistan — A suicide bomber targeting foreign forces in southern Afghanistan killed at least four Afghans and wounded 15 on Wednesday, police and provincial officials said on Wednesday.

The bomb struck in Lashkar Gah, capital of the southern battleground province of Helmand. A police official said there were foreign casualties, but a spokeswoman for the NATO-led force was unable to confirm that.

"The target of the suicide car bomber was a convoy of foreign troops passing from a crowded area in Lashkar Gah city," the provincial governor's spokesman, Omar Zwak, told Reuters.

Two men, a woman and a child, all Afghan, were killed and 15 people were wounded, he said.

Helmand has been the scene of some of the fiercest fighting between the NATO-led force and the insurgents since the overthrow of the Taliban in 2001.