At least seven people have reportedly been killed in Syria Thursday after a drone attack targeted a military academy graduation ceremony in Homs. 

"Seven dead and more than 20 regime officers wounded in a violent explosion in the area of the military academy in Homs, caused by an attack by drones during a graduation ceremony," the Syrian Observatory for Human Rights said, according to the AFP. 

The source of the attack is unclear. 

Syria's defense minister attended the ceremony but left minutes before the strikes, a Syrian security source told Reuters.

"After the ceremony, people went down to the courtyard and the explosives hit. We don't know where it came from, and corpses littered the ground," a witness who claimed to have set up decorations at the event told Reuters.

AFP also is reporting that Syrian state television is describing the incident as a "terrorist attack" and there are a "large number of casualties." 

This is a developing story. Please check back for updates.