The Pentagon said Monday that the weekend airstrike that killed 22 people inside a northern Afghanistan medical clinic was requested by Afghan forces -- who reported being under attack by Taliban fighters -- and not U.S. forces.

“The Afghans advised that they were taking fire,” Gen. John Campbell told reporters at the Pentagon, in a hastily called press conference to correct the record.

“An airstrike was then called to eliminate the Taliban threat and several civilians were accidentally struck. This is different from the initial reports, which indicated that U.S. forces were threatened and that the airstrike was called on their behalf."

However, the revised account does not clarify whether the clinic was targeted in error or whether other mistakes may have been made by U.S. forces.

"If errors were committed we will acknowledge them," said Campbell, the top commander of American and coalition forces in Afghanistan.

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Military sources told Fox News again on Monday that Taliban fighters were firing from inside the hospital.

At least 22 people, including nine local staffers for Doctors Without Borders, were killed and 30 were missing after an explosion Saturday near the hospital, in the northern Afghan city of Kunduz.  

Afghan Security Forces backed by U.S. airstrikes have been fighting there to dislodge Taliban insurgents who have overrun Kunduz.

Campbell confirmed Monday that a USAF AC-130 gunship was the aircraft involved.

He also said there were no changes to rules of engagement to announce, as a result of the incident, and that the investigation would take its course.

Campbell said the Taliban were still in Kunduz City, the provincial capital of Kunduz, and had “chosen to fight from urban areas putting civilians in harm’s way.”

He said Brig. Gen. Richard Kim would be leading the investigation in Kunduz.

Campbell said there would be three independent probes into the incident -- one led by U.S. forces, another by NATO and one from the Afghan military.

Fox News’ Jennifer Griffin and Lucas Tomlinson and The Associated Press contributed to this report.