A senior Iranian official said Sunday that any peace plan that included the removal of Syrian President Bashar Assad from power would be a “red line” for Tehran.

Iran has been a staunch ally of the embattled Syrian president and has sent its forces along its proxy, Lebanese Hezbollah, to help Assad’s military.

A top adviser to Supreme Leader Ayatollah Ali Khamenei told state TV on Sunday that “Iran believes that the government of Bashar al-Assad should remain in power until the end of the presidency term.”
“Assad is …[a] red line because he was elected president by the Syrian people,” said Velayati, adding that “the Syrian people must decide their own fate, and nobody outside Syria’s borders can choose for the Syrian people.”

The comments came amid increasing clashes between Syrian government forces and rebels groups across northern and western Syria, imperiling a monthlong ceasefire ahead of peace talks in Geneva. Meanwhile airstrikes pounded the Islamic State group’s de facto capital of Raqqa, killing dozens, on Sunday.

Al-Qaeda’s Syrian affiliate, the Nusra Front, is playing a leading role on the side of the insurgents, according to the Britain-based Syrian Observatory for Human Rights, a monitoring group with a network of informers inside Syria.

The fighting follows weeks of sporadic government airstrikes, culminating with a raid that killed 33 civilians outside the capital of Damascus on March 31 that tested the durability of a US- and Russia-brokered “cessation of hostilities” that took effect in late February.