US President Donald Trump has urged Russia to hold back on the Syria conflict. The White House said in a telephone call with the Turkish head of state Recep Tayyip Erdogan that he expressed "concern about violence" in the Syrian province of Idlib. Russia should no longer support the "atrocities" of the Syrian government in the civil war country.

Trump also advocated a political solution to the conflict and thanked his Turkish counterpart for Turkey's efforts to "prevent a humanitarian catastrophe."

With the support of Russia, the Syrian army has been taking military action against the rebels dominated by jihadist militias in the Idlib province and parts of the neighboring provinces of Hama, Aleppo and Latakia since December. Syrian ruler Bashar al-Assad is determined to regain control of the region. Turkey is on the side of Assad's opponents who want to defend their last stronghold in the civil war country.

Syrian government forces continued to advance against the militia strongholds on Sunday. After battles and air strikes, the troops had control over "all villages and small towns around Aleppo for the first time since 2012," said the Syrian Observatory for Human Rights.

Turkish delegation travels to Moscow

In the fighting for the province of Idlib there have recently been clashes between Syrian government forces and units of the Turkish armed forces. Ankara has threatened Assad with retaliation if Syrian troops continue to attack the Turkish army. "The regime needs to know this: Turkey will have no borders there should such attacks continue on our troops," said Vice President Fuat Oktay.

This message was also transmitted to Russia. Despite the tensions, a Turkish delegation will travel to Moscow on Monday to discuss the critical situation in Idlib. A Russian delegation was previously in Ankara.

According to the UN, more than 800,000 people have fled the fighting in Idlib since December. Russia and Turkey in Sochi agreed in 2018 to end the fighting in Idlib. However, all fire breaks agreed since then were broken shortly after they came into force.