Syrian President Bashar Al Assad on Tuesday denounced Turkish leader Recep Tayyip Erdogan as a thief for attacking the north-east of his country and again pledged to retake all areas lost to Damascus in years of civil war.
Mr Al Assad made a rare visit to frontlines in north-western Idlib province, near the last major bastion of Turkey-backed rebel forces.
The Syrian leader was surrounded by army commanders and soldiers in the town of Hobeit, which the army took in August as part of a Russian-led offensive to capture Idlib and surrounds.
"Erdogan is a thief and is now stealing our land," state media quoted Mr Al Assad as saying.
Turkey this month began an assault against its Syrian Kurdish militia enemies in Syria's north-east with the help of rebel forces who control large parts of territory north of Idlib.
With the war now in its ninth year, capturing Idlib would be an important victory for the regime, which has steadily recovered control of rebellious areas with Russian and Iranian support.
"We said and continue to say that the Idlib battle is the core to decisively end chaos and terrorism in all of Syria," Mr Al Assad said.
Idlib had a lull in air strikes after Damascus and its ally Moscow declared a ceasefire on August 31. Just before the truce, the offensive made its most significant advance by seizing the strategic city of Khan Sheikhoun.
The campaign also expanded state control of parts of a motorway that stretches from the capital Damascus to the city of Aleppo.
Turkey and Russia had brokered a de-escalation zone deal in 2017 to curb fighting in Idlib. It does not cover hardline militants who are the dominant force in the area.
Many of the 500,000 people uprooted by the fighting in the north-west have fled towards the Turkish border.
The violence in Idlib province and a strip of nearby Hama has marked the biggest military escalation between Mr Al Assad and his insurgent enemies since last summer.