Syrian President Bashar al-Assad has been unwilling to make trade-offs on the writing of the country’s new constitution by a committee formed by Russia, Iran and Turkey, Jerusalem Post said on Saturday.

"The constitution is not subject to bargaining, and we will not allow enemy states to achieve through their Syrian agents who have Syrian nationality any of their objectives. The future of Syria will be exclusively decided by the Syrians," Assad said on Feb. 17, accusing the Syrian opposition participating in drafting the new constitution of being “agents" of Turkey.

Turkey has been supporting rebels who have fought to topple Assad. Turkish President Tayyip Erdoğan repeatedly described Assad as a "terrorist" and said it was impossible for Syrian peacemaking efforts to continue with him.

Another tension point between Damascus and Ankara is the fate of the Syrian Kurds. Turkey sees Syrian Kurdish People's Protection Units (YPG), controlling swathes of area in northern Syria, linked to outlawed Kurdistan Workers' Party that has waged decades-long insurgency for Kurdish self-rule. Syrian Kurds are seeking recognised autonomy within Syria with the new constitution.

“The Turks would be very much against this, as well as the Iranians who want a unified Syria,” Jerusalem Post said.

In recent months, the Kurds have asked Assad to establish a security buffer in the Kurdish-controlled areas against an expected attack from Turkey. Likewise, Assad forces on Dec. 28 entered the northern city of Manbij after an agreement with Kurdish forces to deter Turkey from attacking the city.