The Islamic State group says it carried out bomb attacks in the Syrian capital Damascus and the city of Homs, which left at least 140 people dead.
Four blasts in the southern Damascus suburb of Sayyida Zeinab killed at least 83 people.
Earlier in Homs, 57 people, mainly civilians, were killed in a double car bombing, a monitoring group reports.
Both of Sunday's attacks targeted areas dominated by Islamic minorities reviled by the Sunni Muslim radicals of IS.
The blasts came as President Bashar al-Assad told reporters Syrian refugees should not be scared of returning home.