Iranian Foreign Minister Abbas Araghchi met President Bashar Assad in Damascus on Sunday as Syria launched a counterattack against a surprise assault by insurgents.

Hundreds of fighters from Iran -backed Iraqi militias have crossed into Syria to help the regime of Bashar al-Assad fight off an insurgency across much of the northwest of the country, which has seen the seizure of the second city of Aleppo.

Russia and Iran have offered military and diplomatic support to the Syrian government as it tries to stanch a major rebel advance.

Assad’s regime seemingly came out of nowhere, and as Aleppo fell to Turkish-backed rebels in a matter of days, the Syrian president reportedly flew to Moscow.

In just a few days, a patchwork of rebel forces has seized control of a broad stretch of land in the west and northwest of Syria. But it’s unclear just how much support Syria’s weakened allies can provide.

Approximately 200 Iraqi militiamen crossed into Syria overnight through the strategic Bou Kamal border crossing, according to an opposition war monitor.