Story highlights New report says United States failed to do its "homework" before airstrikes on civilians

Syrian reports say mosque hit; US says al Qaeda meeting targeted

(CNN) A new report suggests American forces failed to take necessary precautions to avoid dropping a pair of bombs on a Northern Syria mosque full of hundreds of worshipers.

Syrians said the US airstrikes hit a western Aleppo mosque on March 16 , killing at least 40 worshipers and injuring dozens more. The US said the bombings targeted a meeting hall hosting al Qaeda terrorists.

But Human Rights Watch said an investigation found no evidence to support the US claim that members of al Qaeda or any other armed group were meeting in the mosque. Interviews with locals and documentary evidence of the building in question suggest it was a well-known mosque that hosted lectures every Thursday between sunset and evening prayers, the group said.

Syria Civil Defense volunteers dig through rubble after a reported airstrike Thursday on al-Jena, Syria.

Any attempt to gather information about the building would have revealed that it was a popular gathering spot for residents at the time of the intended attack, Human Rights Watch said in a new report released Tuesday

"The US seems to have gotten several things fundamentally wrong in this attack, and dozens of civilians paid the price," Ole Solvang, deputy emergencies director at Human Rights Watch, said in a statement. "The US authorities need to figure out what went wrong, start doing their homework before they launch attacks, and make sure it doesn't happen again."

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