At least eight people have lost their lives when a powerful explosion ripped through a heavily secured district of the Syrian capital Damascus.

A police source, speaking on condition of anonymity, said a bomber blew himself up on Thursday evening in the southwestern Kafr Sousa neighborhood of Damascus, where some of Syria's main security installations are located.

Syria’s official news agency SANA reported that a “terrorist” detonated an explosive belt close to a sports club there.

The so-called Syrian Observatory for Human Rights, meanwhile, said the death toll was expected to rise as several of the wounded were in a critical condition.

Footage on state media showed wreckage of several cars and blood splattered everywhere. There were also dozens of heavily armed security personnel at the site of the explosion.

On July 25, 2016, an explosives-laden car blew up close to the main Umayyad Square in the same Damascus neighborhood, leaving several people dead and injured.

The British-based monitoring group said at the time that the blast was near an Iranian school.

Late last year, the Syrian army managed to liberate the eastern sector of Aleppo, the country’s second-largest city, which had fallen to Takfiri groups back in 2012.

Government forces later secured the evacuation of remaining civilians and armed groups from the city under a ceasefire deal with the militant groups, brokered by Russia and Turkey.

The Aleppo deal set the stage for a landmark all-Syria truce deal between Damascus and foreign-backed militant groups operating in the country.

The diplomatic achievements were made following high-level trilateral talks involving Russia, Iran and Turkey over the Syria crisis in Moscow.

Syrian President Bashar al-Assad had earlier hailed the victory in Aleppo as “history in the making” and “a huge step” in bringing the war in Syria to an end.