BEIRUT — The United States said Friday that an airstrike targeted al-Qaida militants in Syria, but residents charged that the powerful attack killed scores of civilians in a nearby mosque.

A Pentagon spokesman, Navy Capt. Jeff Davis, said the United States believes that the strike late Thursday killed “dozens” of members of the terrorist group. Separately, a U.S. official insisted the raid was based on verified human intelligence, targeting al-Qaida groups gathered to discuss future operations.

But local activists and a monitoring group said the airstrike hit a mosque in the western Aleppo countryside during a religious gathering, killing at least 46 people and trapping more under the rubble.

Reached by phone, residents in the town of Jinah described a series of powerful blasts that shook the ground and sent civilians fleeing from the site, many dazed and bleeding.

The United States has struck dozens of locations in northwestern Syria, where an al-Qaida-linked alliance of rebel groups known as Tahrir al-Sham, or HTS, is now the ascendant force. The area is also home to an assortment of other rebel groups, as well as thousands of civilians.

Thursday’s attack involved two Reaper drones, which fired four Hellfire missiles and dropped at least one 500-pound GPS-guided bomb, the U.S. official said, speaking on condition of anonymity to discuss intelligence matters.

Three residents told The Washington Post that at least 200 people had gathered in the mosque and a nearby building for religious teaching sessions at the time of the U.S. attack.

“The mosque in al-Jinah was destroyed. Bodies filled the space,” said Mohamed al-Shaghal, a journalist who arrived at the scene shortly after the attack.

The Syrian Observatory for Human Rights, a Britain-based monitoring network, described a “massacre” and said the dead were mostly civilians. Photographs from the area showed rescue workers pulling mangled bodies from a mound of rubble.

Aerial imagery appeared to confirm that much of the northern section of Jinah’s mosque was destroyed, although it was unclear whether the strike was a direct one.

The U.S. official said the attack included a follow-up airstrike. Mohamed Shakourdi, a local activist, said it came as people streamed out of the mosque.

The mosque was believed to have housed several displaced families from the nearby city of Aleppo, after government forces leveled much of the area during a monthslong campaign to recapture its eastern districts.

“Whether U.S. drones directly targeted the mosque at al-Jinah as some allege — or it was instead caught up in a U.S. drone strike in the immediate vicinity — a significant number of civilians died at the scene, according to the White Helmets, local media and casualty monitors,” said Chris Woods, director of Airwars, a Britain-based group that tracks allegations of civilian casualties.

The organization said the rate of civilian deaths caused by U.S.-led coalition airstrikes, as well as unilateral U.S. actions, was rising “steeply” in both Syria and Iraq.