A car bomb and two suicide bombers attacked the Sayyida Zeinab district, home to Syria's holiest Shiite shrine, as representatives of Syria's government and its divided opposition began convening in Geneva in an attempt to start the first peace talks in two years.
The Syrian state news agency SANA has put the death toll from the attack at more than 50, according to Reuters.
The Britain-based Syrian Observatory for Human Rights, which is close to Syria's foreign-backed opposition said the attack had targeted a military bus carrying forces who were changing guard, and that 42 of the dead were fighters allied to the government.
The Sayyida Zeinab mosque contains the grave of a granddaughter of the Prophet Mohammed (PBUH) and is particularly revered as a pilgrimage site by Muslims.