IRAQI militias have deployed in Syria to back the government’s counteroffensive against a surprise advance by insurgents who seized part of the largest city of Aleppo, a militia official and a war monitor said today.

Insurgents led by jihadi group Hayat Tahrir al-Sham launched a two-pronged attack on Aleppo last week and moved into the countryside around Idlib and neighbouring Hama province. 

Government troops built a fortified defensive line in northern Hama in an attempt to stall the insurgents’ momentum while jets on Sunday destroyed large sections of insurgent-held lines.

Iranian Foreign Minister Abbas Araghchi met Syrian President Bashar Assad in Damascus on Sunday and announced Tehran’s full support for his government. He later arrived for talks in Ankara, Turkey, one of the rebels’ main backers.

Mr Araghchi said: “I clearly announced full-fledged support to President Assad, government, army and people of Syria by the Islamic Republic of Iran.”

He did not further elaborate but Iran has been one of President Assad’s principal political and military supporters, including deploying military advisers and forces after 2011 protests turned into an all-out war.

The Iraqi militias already in Syria mobilised and additional forces crossed the border to support Mr Assad’s government and army, said the Iraqi militia official, who spoke on condition of anonymity.

According to Britain-based opposition war monitor the Syrian Observatory for Human Rights, some 200 Iraqi militiamen on pick-ups crossed into Syria overnight through the strategic Bou Kamal crossing.

They were expected to deploy in Aleppo to support the Syrian army’s pushback against the insurgents, the monitor said.

Devastating Syrian and Russian air strikes on rebel positions continued mostly in Hama and Idlib provinces. 

At least 10 civilians were killed in Idlib city and province, according to the Syrian Civil Defence in opposition-held areas.

Syrian Kurds were fleeing the fighting in large numbers after Turkish-backed rebels seized Tel Rifaat from rival United States-backed Kurdish authorities. 

The Kurdish-led Syrian Democratic Forces largely withdrew and called for a humanitarian corridor to allow people to leave safely in convoys toward Aleppo and later to Kurdish-led north east regions.

The surge in fighting has raised the prospect of another violent, destabilising front reopening in the Middle East at a time when Israel is fighting Hamas in Gaza and Hezbollah in Lebanon, conflicts that have repeatedly threatened to ignite an even wider regional war. 

It also risks drawing Russia and Turkey into direct heavy fighting against each other.

The insurgents announced their offensive on Wednesday, just as a ceasefire started between Hezbollah and Israel.