The leaders of Iran, Russia and Turkey announced  on Monday that an agreement has been finally reached on the composition of a committee tasked with rewriting Syria’s constitution as part of a political solution to the country’s civil war, now in its ninth year.

Turkish President Recep Tayyip Erdogan told journalists at the end of the meeting with Russia’s Vladimir Putin and Iran’s Hassan Rouhani in the Turkish capital Ankara that differences on one last committee member has been overcome, paving the way for the committee to start working as soon as possible.

“We portrayed a constructive and flexible attitude to determine constitutional committee members and rules of procedure. We made an effort for the political process to move forward. In short, hitches regarding the establishment of the committee were eliminated by our mutual efforts,” Erdogan said.

The leaders did not provide a timeframe for the committee — set to be made up of Syrian government and opposition figures — to begin its proceedings. The procedural rules still have to be worked out, Putin told reporters.

“The proceedings must begin rapidly,” Putin said.

“Extremist groups may try and destroy this process because they do not want a final agreement since they gain money from war.”

Russia and Iran are key allies of Syrian President Bashar Assad while Turkey backs Syrian rebels seeking to oust him.

Rouhani said he hoped for elections to take place in Syria in 2020 or 2021.

The leaders also agreed to de-escalate the volatile situation in Idlib — the last remaining rebel stronghold in Syria — while combatting extremists and protecting civilians. A cease-fire that went into effect at the end of August has been holding despite some violations.

Idlib is dominated by the al-Qaida-linked group Hayat Tahrir al-Sham.

Syrian forces, backed by Russia, targeted the armed group in a four-month ground and air offensive but civilians have been widely affected.

Hundreds of thousands of Syrians, some already displaced from other parts of the war-torn country, have moved toward Turkey’s border.

A major conflict in Idlib has raised the possibility of a mass refugee flow to Turkey, which already hosts 3.6 million Syrian refugees.

“We cannot stand by and watch a new tragedy that would affect 4 million people right next to our border,” Erdogan said, adding: “Such a calamitous development would not only affect our country but also all of Europe.”