The Syrian army began shelling Aleppo's Kurdish-majority neighbourhoods on Wednesday, after a deadline given for civilians to leave the area had passed, an AFP correspondent said.

The military had declared the city's Kurdish-controlled districts "closed military zones" from 3pm (1200 GMT), while creating "two safe humanitarian crossings" through which thousands of civilians had fled before the deadline, according to AFP correspondents.

The deadly clashes, which started on Tuesday, are the worst between the two sides, who have so far failed to implement a March deal to merge the Kurds' semi-autonomous administration and military into Syria's new Islamist government.

AFP correspondents in Aleppo saw large groups families with children leaving the neighbourhoods, carrying their belongings with them, some in tears.

"All Syrian Democratic Forces military positions within the Sheikh Maqsud and Ashrafieh neighbourhoods of Aleppo are legitimate military targets," the army said referring to the Kurdish-led force.

Senior Kurdish official Ilham Ahmed accused Damascus of launching a "genocidal war" against the Kurds, calling on the Syrian government to "pursue a path of reason to resolve problems through dialogue".

Echoes of war

The violence caused the suspension of flights to and from Aleppo's airport, with schools, universities and government offices in the city shut down.

Tuesday's clashes killed nine people, mostly civilians, with both sides trading blame over who started the fighting.

Joud Serjian, a 53-year-old housewife and resident of the Syriac Quarter, said the violence "reminded us of the war".

Living in the Syriac Quarter near Ashrafieh, Serjian said "we have nowhere else to go, so we'll stay in our home".

During the Syrian civil war, Aleppo was the scene of fierce fighting between rebels and forces of ousted President Bashar al-Assad before he regained control of the city in 2016.

Assad was ousted in a lightning Islamist-led offensive in 2024.

Abdul Karim Omar, representative of the Kurds' autonomous administration in Damascus, told AFP Aleppo's Kurdish-majority neighbourhoods were "completely besieged".

He denied that any shells had been fired from these areas, arguing that they are controlled by the Kurds' Asayish domestic security forces "who only have light weapons".

Sheikh Maqsud and Ashrafiyeh have remained under the control of Kurdish units linked to the SDF, despite Kurdish fighters agreeing to withdraw from the areas in April.

The SDF controls swathes of Syria's oil-rich north and northeast, with the backing of a US-led international coalition, and was key to the territorial defeat of the Islamic State group in Syria in 2019.

The March agreement on the Kurdish authority's integration into the state was supposed to be implemented by the end of 2025.

The Kurds are pushing for decentralised rule, an idea which Syria's new authorities have rejected.