Syrian President Bashar al-Assad said on March 16 that he would not meet Turkish counterpart Recep Tayyip Erdogan until Turkey was ready to entirely withdraw its military from northern Syria and restore the situation that existed prior to the war in the country that broke out more than a decade ago.

The comments from Assad—who met Russian leader Vladimir Putin in Moscow on March 15—came as Reuters quoted a Turkish foreign ministry source as saying a March 15-16 meeting in the Russian capital of the deputy foreign ministers of Russia, Turkey, Iran and Syria, scheduled for this week, had been postponed to an unspecified date for “technical reasons”. The meeting is meant to take place ahead of planned talks between the top diplomats at a later date, aimed at resolving the conflict in Syria that has left hundreds of thousands dead.

The defence ministers of Ankara and Damascus held landmark talks in Moscow in December, alongside their Russian counterpart. It was the highest-level face to face encounter between Turkey and Syria since the start of the war. But if it signalled rapprochement then the cancellation of the latest planned meeting might indicate the peace process has suffered a setback.

On his Moscow visit, Assad, who is backed militarily by both Russia and Iran, told Russian TV station Sputnik that there was no point in a meeting with Erdogan—who faces a presidential election on May 14—until Turkey's "illegal occupation" ended.

"This is linked to arriving at a stage when Turkey would clearly be ready and without any ambiguity to exit completely from Syrian territory and end its support of terrorism and restore the situation that prevailed before the start of the war on Syria," Assad said in an interview relayed by Lebanon's pro-Iran Hezbollah group's Al-Manar TV station.

"This is the only situation when it would then be possible to have a meeting between me and Erdogan. Aside from that what's the value of such a meeting and why would we do it if it would not achieve final results for the war in Syria."

Assad also said: "We trust the Russian side who has played a mediator role to facilitate the communications, but within the basis of Russian policy of respecting sovereignty of states… and the exit of illegal foreign forces from Syrian territory."

Assad has described the presence of Russian troops in Syria as legitimate because his government requested such support from Moscow. It could be the case, however, that Putin would like to free up some military assets for use in Russia’s war in Ukraine.

Nato member Turkey has been a major backer of armed groups in Syria opposed to Assad, whom Erdogan once described as a “terrorist”.

Turkey has sent its own troops into multiple parts of Syria’s north. It remains the biggest military and political ally of the Syrian opposition, which controls the last rebel bastion in northwest Syria.

Since the conflict began, Iran has remained supportive of the government in Damascus, deploying undeclared forces.