KABUL, Afghanistan, Dec. 8  The Afghan government called on Taliban fighters in the town of Musa Qala in southern Afghanistan to put down their weapons and give themselves up or face a heavy attack from Afghan and NATO forces hemming in the town on Saturday.

Two children were killed and five civilians were wounded when a car came under fire in the town as NATO and Afghan forces closed in during the second day of an operation to retake the town from the Taliban, the Defense Ministry spokesman, Gen. Zaher Azimi, said at a news conference here in the capital.

“The Afghan government and NATO deeply regret the incident, and our message to the insurgents is not to use civilians as a human shield,” General Azimi said. Twelve insurgents were killed in the fighting, and one was arrested, he said.

Musa Qala has been a haven for Taliban and foreign fighters since February, when they moved in four months after British forces pulled out of the town. General Azimi said the plan to retake the town came after tensions rose between local elders and clerics and the hundreds of foreign fighters who had set up in the town. The tribal elders had asked the government to reassert control, he said.