KABUL, Afghanistan — For the second time in less than 24 hours, the American military yesterday acknowledged involvement in an incident that caused multiple civilian deaths in Afghanistan — this time, an airstrike on a rural compound that killed nine people from the same family, according to Afghan authorities.

A day earlier, at least eight civilians died and dozens of others were wounded when American troops opened fire on a busy highway after a suicide bomber attacked their convoy.

In both instances, American military officials blamed insurgents for placing civilians in harm’s way by deliberately staging attacks that were certain to draw American retaliation, and then using civilians as cover.

But the back-to-back incidents appeared to be raising tensions between allied forces and the Western-backed government of President Karzai, which is often the target of popular anger when civilian deaths occur.

Mr. Karzai called yesterday for an investigation of the shootings that took place Sunday morning on a stretch of highway in eastern Afghanistan, near the city of Jalalabad. The president’s office said he condemned the incident.

The American military said its troops fired in self-defense after an ambush by insurgents, but eyewitnesses on the roadway said the American gunfire in the wake of the explosion appeared indiscriminate, some of it taking place miles from the blast site.

American military officials said in a statement that Sunday’s late-night airstrike on a compound in the thinly populated village of Jabar, about 50 miles northeast of Kabul in Kapisa province, was called in after a remote American firebase nearby came under rocket attack.

Men armed with automatic weapons were seen entering the compound, which was targeted with a pair of 2,000-pound bombs, the military said in a statement.

The bombs pulverized the mud-brick structures inside, according to witnesses.

An American spokesman said insurgents had deliberately put the compound’s inhabitants in danger.