Residents and soldiers loyal to Syria’s President Bashar al-Assad inspect damage after a suicide attack in Sayeda Zeinab, a district of southern Damascus, Syria January 31, 2016.

The death toll from a suicide attack in Damascus on Sunday that was claimed by the Islamic State of Iraq and Syria (ISIS) militant group has risen to more than 70, the Syrian Observatory for Human Rights said.

A car bomb and two suicide bombers attacked the Sayeda 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.

The British-based Observatory, which monitors the war using contacts on the ground, said the attack had targeted a military bus carrying Shiite militiamen who were changing guard, and that 42 of the dead were fighters allied to the government.

The Lebanese Shiite militant group Hezbollah and other Iraqi and Iranian militias have a strong presence in Sayeda Zeinab, which is a site of pilgrimage for Shiites from Iran, Lebanon and other parts of the Muslim world.

While much of the Syrian leadership is drawn from an offshoot of Shiite Islam, ISIS espouses a radical version of Sunni Islam and considers other sects to be heretical.

The area witnessed heavy clashes in the first few years of the war, prompting the army and allied Shiite militias to tighten security, notably with roadblocks.