Three blasts have killed more than 70 people and wounded at least 40 in Syria's capital Damascus, a monitor said.
The explosions, one of which was caused by a car bomb, occurred near the Shia Muslim shrine of Sayyida Zeinab on Sunday, the UK-based Syrian Observatory for Human Rights said.
The Observatory said several Shia militia fighters were among the dead, adding that the casualty number was expected to rise.
State television footage showed burning buildings and car wreckage in the neighbourhood where the shrine is located.
The Islamic State of Iraq and the Levant (ISIL) claimed responsibility for the attack, according to Amaq, a news agency that supports the group.
It said two operations "hit the most important stronghold of Shia militias in Damascus".
The heavily populated area of southern Damascus is a site of pilgrimage for Shias from Iran, Lebanon and other parts of the Muslim world.
The shrine houses the grave of the daughter of Ali ibn Abi Taleb, whom Shias consider the rightful successor to Prophet Mohammad. The dispute over the succession led to the major Sunni-Shia schism in Islam.
The shrine has been targeted before, including in 2012 and in February 2015, when two suicide attacks killed four people and wounded 13 at a checkpoint nearby.
In the same month, a blast ripped through a bus carrying Lebanese Shia Muslim pilgrims headed to Sayyida Zeinab, killing at least nine people in an attack claimed by the armed group al-Nusra Front.
Trading blame
The latest attacks came as the United Nations' plan to hold negotiations on ending the Syrian war was dealt a new blow, as opposition and government delegations traded charges against each other.
Syria rivals trade blame over stalled talks
Delegates from the Syrian government and the country's main opposition bloc in Geneva accused each other of not being serious in creating conditions for meaningful talks.
Salem al-Meslet, spokesman for the opposition's High National Committee (HNC), told reporters on Sunday that the bloc would not join the talks before the implementation of their humanitarian demands.
Syrian ambassador to the UN Bashar Jaafari, who is leading the government delegation, said Damascus will not accept preconditions for negotiations.
Jaafari branded the opposition as terrorists backed by foreign powers, but said his government was considering humanitarian moves as demanded by the opposition delegation.
