Twin blasts Saturday in Damascus, Syria, killed at least 40 Iraqi pilgrims and wounded 120 more, according to Iraq's Foreign Ministry.
The explosions took place at the Bab al-Saghir Cemetery in the Syrian capital.
The attackers used improvised explosive devices, Iraqi Foreign Ministry spokesman Ahmed Jamal said in a statement.
The pilgrims were visiting "holy shrines," the ministry said.
Bab al-Saghir is a sacred cemetery where descendants and companions of the Prophet Mohammed are buried.
It is in the southern section of the old city in Damascus and is one of Syria's largest and oldest cemeteries.
Shiites customarily have made pilgrimages to the site since descendants of Ali, the prophet's cousin, were buried there.
Sunni terror groups such as ISIS have attacked these Shiite shrines.
Last year, ISIS claimed responsibility for deadly attacks near the revered "Lady Zeynab" Shiite Muslim shrine on the southern outskirts of Damascus. Iraq has endured such attacks as well.
Syria has been engulfed in a civil war for six years, and it has been marked by Sunni-Shiite sectarian conflict.