A huge explosion near a military intelligence office in the Syrian capital of Damascus has killed a number of people.
"The explosion took place near a security branch in the south of the city," said the UK-based Syrian Observatory for Human Rights (SOHR)
"There are some people killed and injured but we could not verify the toll immediately."
Rami Abdel Rahman, head of the monitoring centre, said the explosion appeared to be the first attack in Damascus in over a year.
The SOHR said it was unclear if the blast was caused by a bomb or suicide attack, but that shooting followed the explosion.
Earlier, Syrian state television reported that a blast had been heard around the southern highway in Damascus.
It said first reports suggested a "terrorist act".
Syria is locked in a civil war that has killed more than 360,000 people and displaced millions since a crackdown on anti-government protests in 2011 exploded into full conflict.
President Assad's forces, backed by Russian military, have retaken large parts of Syria from rebels and jihadists, and now control almost two-thirds of the country.
The Syrian regime in May reclaimed a final piece of territory held by the Islamic State group in southern Damascus, giving it total control over the capital for the first time in six years.
