Since the multinational anti-terrorist coalition led by the United States launched an offensive on Iraq’s Mosul in mid-October, there has been no shortage of criticism from Moscow and Damascus. Russian diplomats and the military tend to downplay the coalition’s successes and emphasize its failures, claiming it’s frequently hitting civilian targets — something for which the West itself bitterly criticizes Russia and Syria.

But the most worrisome thing for Moscow — as Russian Foreign Minister Sergey Lavrov made clear after an Oct. 28 meeting with his Syrian counterpart, Walid Moallem — is the prospect of a large-scale movement of Islamic State (IS) fighters from Iraq into Syria. Russia Today, an English-language news site funded by the Russian government, cited undisclosed sources as saying American and Saudi intelligence services have an agreement to allow thousands of militants passage to Syria to prepare a further offensive on Palmyra and Deir ez-Zor, which are partly controlled by Syrian President Bashar al-Assad and allied Shia forces.

On Oct. 25, Lt. Gen. Sergei Rudskoi, head of the Main Operative Directorate of the Russian Armed Forces General Staff, stated that about 300 IS militants had arrived from Mosul to Deir ez-Zor.

These statements, however, carry more of a political message than a military posture. Moscow and Washington have been facing off in a battle for public relations superiority since the beginning of the Syrian war and are jumping at any opportunity to poke one another with reproaches and occasional threats. Moreover, after the start of the operation in Mosul, the coalition limited journalists’ access to the frontline, restricting their news feed to a trickle of official press releases. In Moscow, this was seen as an attempt to cover up the coalition’s losses while exaggerating its achievements and diminishing those of IS.