Jets hit around a mosque in al-Jina village near Atarib in the western part of Aleppo province, a few miles (km) from Idlib province on Thursday, killing at least 46 people, mostly civilians, the Syrian Observatory for Human Rights said.
Syrian opposition activists said around 40 people, mostly civilians, were killed in a mosque in the area, accusing the USA -led coalition of carrying out the airstrike Thursday evening.
The Pentagon on Friday denied accusations by a Syrian rebel group that the United States had targeted a mosque in Syria and, in a rare move, showed an aerial image to illustrate the mosque was intact and the building destroyed was in fact across the street.
The US has been bombing jihadists in war-torn Syria as part of an global coalition since 2014.
Davis said the military was "not aware of any credible allegation" of civilian casualties despite the emerging accounts from Syrian watch groups.
The apparent mosque strike comes just a few days after it was revealed that the Trump administration has relaxed Central Intelligence Agency protocol on drone strikes against suspected terrorists.
Abu Muhammed, a village resident, said that he "heard powerful explosions when the mosque was hit. It was right after the prayer at a time where there is usually religious lessons for men in it".
It has since escalated into a full-scale conflict that has left hundreds of thousands of people dead and more than half of the country's prewar population displaced inside and outside of Syria.
A cessation of hostilities was brokered by rebel backer Turkey and regime ally Russian Federation in December, but violence has continued across much of the country.
The US-led coalition, meanwhile, has been bombing jihadist groups in Syria since 2014.
A Reaper military drone flew over the site for 30 minutes after the strikes and did not see anyone leaving the small mosque, even though many would be expected to be at prayer during that time, a defense official told BuzzFeed News, who asked for anonymity because they were not authorized to speak to the press.
She continued, "They say that dozens of people were killed in the strike there and that several people are believed to be still alive under the rubble". Monitoring groups say the number is much higher.