UPDATE 2-Blast heard on southern edge of Damascus - state TV

An explosion was heard near a highway at the southern edge of Syria's capital Damascus on Sunday morning, Syrian state media reported.

The head of the city's civil defence, Asef Hababe, told Reuters the blast came from military technicians detonating a bomb. State TV had said earlier that initial reports pointed to a terrorist attack, and that a number of people were injured.

The Syrian Observatory for Human Rights, a UK-based war monitoring group, said the blast struck near a security post. Syria's war has killed hundreds of thousands of people, forced more than half its pre-war population from their homes and dragged in global powers.

With Russian and Iranian help, Syrian President Bashar al-Assad's military has beaten back rebels and Islamic State to restore control over most of the country. (Reporting by Nayera Abdallah; Editing by Michael Perry and Andrew Heavens)