"In Syria, we are living through historic moments as we witness the fall of the authoritarian regime in Damascus," said Mazloum Abdi, who heads the Syrian Democratic Forces (SDF) that controls swathes of northeast Syria, said in a statement on Telegram.

"This change presents an opportunity to build a new Syria based on democracy and justice that guarantees the rights of all Syrians," he added.

Islamist militant group Hayat Tahrir al-Sham and allied factions have pressed a lightning offensive since November 27, seizing swathes of the country from government hands, including major cities Aleppo, Hama and Homs, and entering the capital Damascus early Sunday.

Provinces in the south and east, most notably Daraa, the birthplace of the Syrian uprising, fell into insurgent hands after local armed groups took control when Syrian army forces withdrew.

Abdi on Friday said he hoped for "de-escalation with HTS and the other parties, and we want to resolve our problems through dialogue", including with Turkey.

"The surprise for us is the rapid collapse of the Syrian Army on the front lines and the conquest of vast areas" by the insurgent groups, he told journalists in northeastern city of Hasakeh.

He pointed to communication led by the United Nations in a bid to include the Kurds in negotiations aimed at finding a "political solution" to the Syrian conflict.

Syria's Kurdish minority, which established a semi-autonomous administration in northeastern Syria, were excluded from previous rounds of UN-sponsored negotiations in Geneva between the government and the opposition.

In recent years, Kurdish forces have been the target of several offensives launched in northern Syria by neighbouring Turkey and its allied forces.

* This story was edited by Ahram Online.