File photo. Photograph:( Reuters )
The explosion came as another bomb in the northern city of Afrin killed three people and wounded nine others, according to a war monitor.
A bomb blast hit the capital of war-torn Syria on Sunday and a "terrorist" was arrested, state media said, in a rare attack in the city that has been largely insulated from violence.
The explosion came as another bomb in the northern city of Afrin killed three people and wounded nine others, according to a war monitor, on the first anniversary of a Turkish offensive on the Kurdish-majority region.
Also on Sunday Israel said it intercepted a rocket fired from Syria after Damascus accused the Jewish state of carrying out air raids on the south of the country.
State news agency SANA said a "bomb blast" had hit southern Damascus "without leaving any victims".
"There is confirmation of reports that a terrorist has been arrested," it said.
The Britain-based Syrian Observatory for Human Rights war monitor reported, however, a "huge explosion" near a military intelligence office in southern Damascus that left a number of people dead and wounded.
"The explosion took place near a security branch in the south of the city," and was followed by shooting, said the monitor which relies on a network of sources inside the country.
"There are some people killed and injured but we could not verify the toll immediately," it added.
It was unclear if the blast was caused by a bomb that was planted or a suicide attack, according to the monitor.
There was no immediate claim of responsibility.
Syria is locked in a civil war that has killed more than 360,000 people and displaced millions since a brutal crackdown on anti-government protests in 2011 spiralled into full conflict.
With key military backing from Russia, President Bashar al-Assad's forces 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 scrap of territory held by the Islamic State group (IS) in southern Damascus, cementing total control over the capital for the first time in six years.
Observatory chief Rami Abdel Rahman said that Sunday's blast appeared to be the first attack in Damascus since a car bomb over a year ago that caused no casualties.
Damascus has been largely spared the worst of the violence during the country's nearly eight-year war, but several bomb attacks have shaken the city.
In March 2017 a double suicide attack claimed by Al-Qaeda's former affiliate in the country killed 74 people, including dozens of Iranian pilgrims visiting religious sites in the historic Old City.
That was followed a few days later by bombings claimed by IS at a courthouse and restaurant that killed 32 people.
One of the most high-profile attacks in the capital saw a bomb kill Assad's brother-in-law Assef Shawkat -- a top security official -- and the minister of defence at a command centre in July 2012.
Since reclaiming control of Damascus and surrounding regions, security forces have removed many of the checkpoints that dotted the city.
Government troops have largely pushed remaining rebel and jihadist forces into the northwestern province of Idlib, while IS holds a few dwindling pockets of territory.
The Afrin blast was the result of a bomb placed in a bus in the centre of the city, according to the Observatory.
Turkish troops and allied rebel groups seized the Afrin region from Kurdish forces in March last year after a two-month air and ground offensive.
Israel meanwhile said a rocket fired from Syria's Golan Heights had been intercepted by its "Iron Dome" air defence system.
It came after SANA, quoting a Syrian military source, said anti-aircraft defences went into action after Israel on Sunday launched air strikes on the south of the country.
Israel has pledged to stop arch foe Iran from entrenching itself militarily in neighbouring Syria and says it has carried out hundreds of air strikes there against Iranian targets and those of Tehran's Lebanese ally Hezbollah.