Syrian negotiator Bashar Jaafari attacked the Turkish military presence in the northwest of the country and called Syria's ceasefire statement on Thursday "a test of Turkey's intentions".

The comments came during the second day of talks brokered by Syria's allies Russia and Iran, along with rebel-backer Turkey.

Jaafari also called on the guarantors of the talks to assume "their responsiblities by putting pressure on Turkey" to fulfil the conditions of an accord struck last year.

"The ceasefire agreement is conditioned on Turkey upholding the Astana and Sochi agreements by disarming terrorists of heavy and medium weapons," Jaafari said.

Jaafari accused the militant groups of shelling areas under regime control in northwest Syria "from areas Turkey controls in Idlib."

"Even though we are patient, this time our patience will be limited. We will not be waiting endlessly for Turkey to fulfil its commitments," he said.

Syria's state news agency SANA reported Thursday that the government had agreed to a truce in Idlib on condition a Turkish-Russian buffer-zone deal is implemented.

It cited a military source who announced the regime's "approval for a ceasefire in the de-escalation zone in Idlib starting from tonight" on the condition that jihadists and rebels withdraw forces and weaponry from a buffer zone as per a September accord.

Moscow welcomed the statement.

Idlib is the last major jihadist-run bastion in Syria after eight years of brutal conflict.

Idlib and parts of the neighbouring provinces of Aleppo, Hama and Latakia are under the control of Hayat Tahrir al-Sham, a jihadist group led by Syria's former Al-Qaeda affiliate.

The region is supposed to be protected from a massive government offensive by a September buffer zone deal, but it has come under increasing bombardment by the regime and its Russian ally over the past three months.

A joint statement on the talks in Kazakhstan's capital Nur-Sultan released by Russia, Iran and Turkey showed little progress towards ending Syria's conflict.

The war in Syria has killed more than 370,000 people and displaced millions since it started in 2011 with a crackdown on anti-government protests.