DAMASCUS -- At least 45 people were killed and 100 others wounded when two explosions rocked a Shiite district protected by members of the Lebanese Shiite Hezbollah group south of the capital Damascus on Sunday, Syria's Interior Ministry and a security source told Xinhua.

The twin bombings rocked the sprawling Sayyidah Zaynab district in the southern countryside of Damascus, where a key Shiite shrine with a tomb of Zaynab, the granddaughter of Islam Prophet Muhammad, is located.

A source told Xinhua that the first explosion was caused by a suicide car bombing that ripped through the al-Sudan street in that area, adding that after the first bombing, a suicide bomber detonated his explosive belt in a crowed of people, who gathered at the blast site.

The source said the death toll could likely rise due to the number of critically wounded people, adding that the two bombings took place just 700 meters east of the shrine.

The Sayyidah Zaynab tomb became a center of religious studies of the adherents of the Shiite sect of Islam and a destination of mass pilgrimage by Shiite Muslims from across the Muslim world.

On June 14, 2012, a suicide car bomb tore through that district, wounding around 14 people.

Since mid-summer 2012, the district has been under frequent attacks and shelling by the ultra-radical rebels, who aim to attack the Shiite people due to their supportive stance on the Syrian government and their religious background about the Shiite-Sunni conflict.

As the district holds religious significance to the Shiite people, Hezbollah sent fighters to protect the shrine and manned checkpoints sounding it.