Syria's Kurds on Thursday declared a federal region in the country's north, officials told AFP, but both the government and an opposition coalition swiftly rejected the announcement.

Two officials at talks involving Kurdish, Arab, and other parties in the town of Rmeilan said delegates had agreed on creating a "federal system" unifying the three mainly Kurdish cantons in northern Syria.

"We have given our blessing for the establishment of a federal system in Rojava (the three cantons) and northern Syria," said Aldar Khalil, a member of the conference's preparatory committee.

The declaration risks angering Turkey which is wary of any bid by Syrian Kurds to solidify their autonomy.

The move will centralise governance in areas that Kurdish parties and their allies already control.

The borders and other administrative details concerning the region would be discussed on Thursday, officials said.

Citing a foreign ministry official, Syria's state news agency said the Kurdish declaration "has no legal basis" and would "encroach on Syria's territorial unity".

The opposition National Coalition warned in a statement against "any attempt to form entities, regions, or administrations that usurp the will of the Syrian people."

The opposition High Negotiations Committee, which is involved in peace talks under way in Geneva, has also rejected a federal system for the country.

Kurdish officials have insisted the move will not be a first step towards independence.

Kurdish parties already operate a system of three "autonomous administrations" in Syria's north, with independent police forces and schools.

The three cantons run along Syria's northern border with Turkey and are known as Afrin and Kobane, both in Aleppo province, and Jazire in Hasakeh province.