Russian President Vladimir Putin warned on Friday that ISIS militants held in northeast Syria could escape as a result of a Turkish military operation there, the Interfax news agency reported.
"There are zones located in the north of Syria where ISIS militants are concentrated. They were guarded until now by Kurdish armed forces. Now the Turkish army is going in, the Kurds are abandoning these camps. They could just escape," Putin was quoted as saying.
"I'm not sure if the Turkish army can rapidly get this under control," Putin added, speaking during a visit to Turkmenistan, Reuters reported.
"We should simply understand this, know and mobilize the resources of our security services to neutralize this emerging new threat," he stressed.
Turkey launched its offensive against the Kurdish People's Protection Units (YPG) after US President Donald Trump surprised Washington's allies in the fight against ISIS by pulling out US troops along the Syria-Turkey border.
Turkey considers the YPG an existential threat and as terrorists with close links to a decades-long insurgency within its own border led by the Kurdistan Workers' Party.
However, according to AFP, this view is not shared by many other countries, which have hailed the key role played by the Kurds in dislodging ISIS from Syria after years of fierce fighting.
Meanwhile, Russia's Ministry of Foreign Affairs on Friday called on Ankara and others to show restraint in northeast Syria.
The ministry said in a statement it was important not to allow the situation there to be further destabilized, calling what was happening a matter "of the most serious concern."
It also called for talks to be held between the Syrian government and Kurdish forces and said it was ready to help facilitate such dialogue.