DAMASCUS, Syria, (AP) -An explosion at an ordnance depot that was blamed on summer heat killed at least 15 soldiers Thursday and wounded 50 others in northern Syria, the state news agency said.

The SANA news agency reported that the explosion was “not the result of sabotage” and resulted from “the combustion of sensitive, highly explosive material caused by extremely high temperatures.”

Witnesses said high temperatures, which reached 113 degrees Fahrenheit, also caused fires in northern Syria starting Wednesday night that might have spread to the military complex.

The depot belonged to a military unit in Musalmiya, about 200 miles north of Damascus, SANA said.