Washington ? It appears gunfire, rather than an errant bomb dropped by the United States, was responsible for scores of deaths reported in a central Afghan province, defense officials said Tuesday.

And the attacks involved American raids in several locations, rather than the one previously reported, a senior defense official said on condition of anonymity.

Residents and officials said dozens of civilians, including women and children, were killed in an attack early Monday in the village of Kakarak, about 175 miles southwest of the capital of Kabul. Estimates of those killed ranged from about 40 to more than 100.

But in calling for measures to guard against such accidents, Afghan Foreign Minister Abdullah said Tuesday in Kabul that four village were attacked.

Asked about that report, a senior defense official in Washington said U.S. forces were conducting a reconnaissance operation that targeted several suspected al-Qaida or Taliban locations.

U.S. military officials had said Monday that any of three things could have caused the civilian casualties. One was a malfunctioning bomb from an Air Force B-52 that was striking cave and bunker complexes in the vicinity.

But two defense officials said Tuesday that it had been learned an American soldier on the ground saw the bomb fall in a remote, uninhabited area.

Another possibility that remains is that the civilians were hit by fire from a U.S. AC-130 that was supporting the reconnaissance operation, striking at what Americans believed was anti-aircraft sites. The AC-130 gunship lays down a field of fire from Gatling guns, cannons and 105 mm howitzers.

The other possibility is that enemy anti-aircraft artillery meant for the American plane fell back to the ground.

U.S. investigators Tuesday were taking reporters and Afghan government representatives to the site.

Pentagon spokesman Lt. Cmdr. Jeff Davis said Monday that the B-52 bomber attacked a cave complex in the general area of Uruzgan province. It dropped seven precision-guided, 2,000-pound bombs and one went astray.

But two Pentagon officials said Tuesday that the military was on the verge of ruling that out as the cause of the deaths and injuries.

At about the same time as that bombing mission, a separate reconnaissance operation involving an undisclosed number of regular and special U.S. forces was under way in the same vicinity.

It targeted several enemy locations, but it’s unclear whether that meant several buildings, compounds or villages, one defense official said.

An American on the ground for that operation reported fire from anti-aircraft artillery sites and called in the AC-130 gunship to counterattack, Davis said.

Survivors say planes attacked a wedding, perhaps mistaking celebratory fire from the party for anti-aircraft fire.

Whatever the explanation, the matter is a reminder that the mission in Afghanistan is dangerous, not only for American and allied forces searching for al-Qaida and Taliban fighters but also for Afghan civilians. If the attack turns out to have been a deadly error by U.S. forces, it would not be the first time that human or mechanical error led to unintended deaths and injuries there.

Just last week, U.S. Central Command said it had determined that two Air National Guard F-16 pilots were primarily to blame for the mistaken bombing in April of Canadian forces in southern Afghanistan. One pilot dropped a 500-pound bomb that killed four Canadian soldiers and injured others.

On May 31, U.S. troops mistakenly killed three of their Afghan allies in a firefight that broke out when both sides moved separately into a compound mistakenly thought to be a hide-out of Taliban and al-Qaida leaders.

About 7,000 U.S. troops are in Afghanistan. They have conducted little aerial bombing in recent months and have engaged in little direct ground combat since March.

Much of their work is going out on patrols looking for the enemy, watching sites al-Qaida and Taliban may use to hide, finding weapons caches and so on.