An explosion at an arms depot in northern Syria has killed 15 soldiers and wounded 50, the Sana state news agency has said.
The explosion took place early in the morning at Musalmiya, about 10km (6 miles) north of the city of Aleppo.
"One hospital I went to was filled with injured personnel," a witness told the Reuters news agency.
Officials say the blast was caused by high summer temperatures, up to 50C, which set off explosive materials.
It was "not the result of sabotage", they said.
"There is a heat wave and temperatures reached close to 50C degrees, which caused an ammunition dump to explode," an official told Reuters.
Syria has seen violence by Islamic extremists in recent years, with security forces clashing several times with militant groups.
An official at Aleppo University Hospital told the Associated Press news agency that the bodies of five dead soldiers and 10 wounded were brought to the facility.
Officials also visited the wounded at the Kindi hospital.