JABAR, Afghanistan — A coalition airstrike destroyed a mud-brick home after a rocket attack on a U.S. base, killing nine people from four generations of an Afghan family including a 6-month-old, officials and relatives said Monday — one of the latest in a string of civilian deaths that threaten to undermine the government.

It was the third report in two days of U.S. forces killing civilians.

President Hamid Karzai condemned the bombing, “which caused the American forces to fire on civilians,” and a statement said relatives of the dead wanted the “perpetrators” brought to justice.

The U.S. military blamed militants for putting innocent lives in danger. A villager in Kapisa, about 50 miles northeast of the capital, confirmed the U.S. account that a rocket was first fired at the American base.

The political fallout could resonate widely among Afghans, analysts said.

Civilian deaths “encourage people toward the Taliban and give the Taliban a chance to turn the situation to their advantage,” said Mohammad Qasim Akhgar, an Afghan political analyst and spokesman for the non-governmental Freedom of Expression Association.

In the Kapisa province violence, the U.S. military said a rocket was fired at a hilltop U.S. base, prompting return fire by the coalition forces and the airstrike.

Two men with automatic rifles were seen leaving the site of the rocket attack and heading into a compound that was then hit by two 2,000-pound bombs, a military statement said. Rural homes in Afghanistan are built in a compound style with one large outer wall often encasing several small rooms; many families tend to share the same compound.

“These men knowingly endangered civilians by retreating into a populated area while conducting attacks against coalition forces,” said Lt. Col. David Accetta, a U.S. military spokesman. “We observed the men entering a compound and that compound was targeted and hit by an airstrike.”

The bombs left a large crater of twisted lumber and chunks of mud and killed four women, four children between the ages of 6 months and 5 years, and an 80-year-old man, said Gulam Nabi, a relative of the victims.

Among those killed were Gulam Nabi’s parents, his sister, two female relatives by marriage and four of the extended family’s youngest children.