Syrian blast kills 15

 DAMASCUS, Syria (Reuters) -- An explosion at a military complex in northern Syria killed 15 soldiers and wounded 50 on Thursday.

Authorities said the blast, which was heard 20-kilometers (13 miles) away, was caused by an accident. Syrian television said the explosion was "not a terrorist act".

"There is a heat wave and temperatures reached close to 50 degrees, which caused an ammunition dump to explode," one official told Reuters.

Witnesses said the blast took place early in the morning at a military area housing a special forces unit and an infantry school in the Muslemiah area north of the city of Aleppo.

"Several soldiers arrived dead at one hospital. They had bad shrapnel wounds," one witness, who declined to be named, said by telephone from Aleppo.

One diplomat in the Syrian capital said it was plausible for the explosion to have been triggered by the heat. "High temperatures have been the norm for a while and storage conditions could have been better to say the least," the diplomat said.

Officials from Aleppo, one of the most religiously conservative cities in Syria, visited the wounded at the Kindi hospital in the city.

Northern security installations were a target for Muslim Brotherhood fighters during the early 1980s, when they waged a revolt against the secular government of late President Hafez al-Assad, father of the current president Bashar.

Stability has been Syria's hallmark since government forces crushed the revolt, although security forces thwarted attacks on the U.S. embassy and state television last year.

The government has intensified a campaign against what it describes as religious extremists in the past few months, including raids in the north. Hundreds have been arrested and scores killed in confrontations with security forces.

Northern Syria also has a concentration of Syria's Kurdish minority, who demand that tens of thousands of disenfranchised Kurds be granted citizenship. President Bashar al-Assad recently promised to address the issue.

Syria has been ruled by the secular Baath Party since 1963, when it took power in a coup. Assad began a second 7-year term this month, saying that maintaining stability and countering Washington's attempts to undermine Syria's government were his priority.