The jets struck the village, south-west of Atarib near Aleppo, as the mosque was full of worshippers at evening prayer, said the Observatory, which monitors the Syrian war via a network of contacts across the country.
The US military said it carried out an air strike on Thursday against al Qaeda militants, killing several, at a meeting location in Idlib province, but it was unclear if it was referring to the attack on al Jina.
Air raids in Syria's Aleppo province kill at least 19
The statement from US Central Command made no mention of civilian casualties.
Syrian and Russian military have also carried out many air strikes in Idlib and Aleppo provinces during the war.
The area is located in one of the main rebel-held parts of Syria, the north-west that includes Idlib province and the western parts of Aleppo province, and its population has been swollen by refugees, UN agencies have said.
Rebels in north-west Syria fighting to oust President Bashar al Assad also include groups supported by Turkey, the United States and Gulf monarchies.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ