According to Syrian media, a suicide bomber detonated an explosive belt inside the St. Elias church on Sunday.
Witnesses on the scene said the destruction was extensive and the attack may have claimed a large number of lives. Rescue services on the scene initially reported that they could confirm 15 fatalities. Later, the state-controlled news agency Sana reported that the number of dead had risen to 20.
According to the same source, which refers to local authorities, at least 50 people have been injured.
The perpetrator opened fire on the churchgoers inside the church before detonating the suicide belt, according to the first eyewitness accounts of the attack.
A person who was in a store opposite the church stated that shots and an explosion were heard and at the church, "the remains of wooden benches that were thrown all the way to the entrance" were seen.
Ziad, 40, said from a store opposite the church that he heard gunfire and then an explosion, and added that "we saw fire in the church and the remains of wooden benches that were thrown all the way to the entrance".
The attack took place in the Dwelaa district, and according to unconfirmed reports, the perpetrator belonged to the terrorist movement IS.
The attack is the first of its kind in the Syrian capital since Islamist rebels overthrew the long-time dictator Bashar al-Assad's regime. Security is still one of the biggest challenges for the country's new authorities.
