The Kurdish People's Protection Units (YPG) “that controls the region by force does not have the right or authority to make a statement or invite other elements on behalf of the local population," the defence ministry said.
"We warn all parties to stay away from provocative actions and rhetoric that will make the region more unstable,” it continued.
The Syrian army was deployed to Manbij in response to the calls of the local population, the army announced on Friday.
The international coalition, however, which has US and French troops in Manbij, contradicted the Syrian Army claim their forces were in the city.
“Despite incorrect information about changes to military forces in the city of Manbij, Syria, [the coalition] has seen no indication that these claims are true. We call on everyone to respect the integrity of Manbij and the safety of its citizens,” the coalition tweeted.
The reported Syrian deployment came after the YPG publicly invited the regime forces to defend the city from a Turkish attack while the Kurdish forces focus their attention on the war against ISIS in Deir ez-Zor province.
Turkish forces and their Syrian militia allies have beefed up their troop numbers and hardware in northern Syria, along the contact lines with the YPG in anticipation of an offensive on Manbij and eastward across the Euphrates River into the Kurdish territory of Rojava.
Ankara considers the YPG a branch of the PKK and has framed its operation as counter-terrorism.
Turkish President Recep Tayyip Erdogan accused his Syrian counterpart Bashar al-Assad of playing a “psychological” game.
“We know that there is a situation like waiving their own flag there, but there is nothing definite there yet,” he said in response to the Syrian army deployment.
Erdogan has repeatedly demanded that the YPG depart from Manbij and he said on Friday that if they have indeed left, “then there is no job left for us.”
Tensions have skyrocketed in northern Syria after US President Donald Trump announced he was pulling American forces out of region. The US troops are on the ground fighting ISIS alongside their partners in the Kurdish-led Syrian Democratic Forces (SDF) and have played peacekeeper between the Kurds and Turkey.
A Turkish delegation, including its defence and foreign ministers, will visit Moscow on Saturday. Russia is a key partner of Assad and Erdogan. A Kurdish delegation visited the Russian capital last week.
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