Following a summit in Ankara, the presidents of Iran, Turkey, and Russia have expressed determination to "speed up their efforts to ensure calm on the ground" in Syria.
Turkish President Recep Tayyip Erdogan, Vladimir Putin of Russia, and Hassan Rohani of Iran agree that the conflict can be ended "only through a negotiated political process," according to a joint statement posted on Rohani's website on April 4.
Erdogan hosted his Russian and Iranian counterparts for the second such tripartite summit on war-ravaged Syria in less than six months.
The three leaders said they were also determined to "protect civilians in the de-escalation areas as well as to facilitate rapid, safe and unhindered humanitarian access to these areas," the statement said.
Iran, Turkey, and Russia are deeply involved in the seven-year war, cooperating to create "de-escalation zones" to reduce fighting while backing separate sides: Russia and Iran support President Bashar al-Assad while Turkey supports rebels seeking his ouster.
They have also sponsored a series of negotiations on the Syrian conflict in Kazakhstan’s capital, Astana, which they argued were a parallel process to support UN-supported peace talks in Geneva.
Russia and Iran have given crucial military and diplomatic backing to Assad's government throughout the war, which began with a government crackdown on protesters and has killed hundreds of thousands of people.
Relations between Russia and Turkey soured badly after Turkish jets shot down a Russian warplane near the Syrian border in November 2015, weeks after Moscow began a campaign of air strikes that shored up Assad and turned the tide of the war.
But Putin and Erdogan have taken steps to mend ties since then as both countries’ relations the West have deteriorated.
After bilateral talks with Putin in Ankara on April 3, Erdogan said Turkey and Russia would continue their cooperation "focusing on our common interests" in Syria.
Rohani held separate talks with Erdogan and Putin on April 4 ahead of the trilateral summit.
Before travelling to the Turkish capital, the Iranian president said that foreign forces operating in Syria without approval from the Damascus government should leave.
Iranian state TV quoted Rohani as saying late on April 3 that he would discuss with Erdogan and Putin Syria’s reconstruction and work on a new constitution.
The three presidents held a similar three-way meeting in the Russian city of Sochi in November.
The aim of the Ankara gathering is to "reorganize and renegotiate the zones of influence in Syria as well as to reflect on the future of Syria's north after U.S. withdrawal," Jana Jabbour, a professor of political science in Paris, told the AFP news agency.
Elizabeth Teoman of the Washington-based Institute for the Study of War (ISW) said that "Erdogan likely wants to use the summit to secure Russian and Iranian support for expanded operations in northern Syria or Iraq."
On April 3, U.S. President Donald Trump said he wanted to decide "very quickly" whether to withdraw U.S. troops from Syria now that they have nearly completed their primary mission of defeating the Islamic State (IS) extremist group.
In addition to carrying out air strikes against IS, the United States has deployed about 2,000 troops in Syria, including U.S. special operations forces who have advised the Kurdish-led Syrian Democratic Forces (SDF) and helped them recapture territory from IS.
Turkey's military and pro-Ankara rebels seized the SDF-controlled Afrin enclave in northwest Syria last month, disregarding U.S. warnings that such a move could destabilize the region further.
Erdogan has indicated that Turkey could extend its operation to other areas near its southern border that are controlled by fighters led by the Kurdish People's Protection Units (YPG) militia, which Ankara considers as a terrorist organization.
Jabbour said that Moscow and Tehran would give free rein to Ankara against the YPG in exchange for bringing the Turkish-backed Syrian rebel groups to the negotiating table.
More than 340,000 people have been killed and millions have been internally displaced or have fled Syria since the conflict broke out following antigovernment protests in 2011.