"We very much hope that the steps that are being taken now — our cooperation with Turkish and US colleagues — will allow regional security and stability to improve instead of degrading. The events of the past few days, are, unfortunately, seeding unoptimistic thoughts", Shoigu told participants of a security forum in Beijing.
"Some camps and facilities where terrorists from several dozen countries have been kept are currently not under guard, and terrorists have started to disperse", the Russian minister stressed.
He also noted that Moscow sees this as a problem which "should be solved immediately, and not only at the Russia-Turkey-US level".
The statement comes during a short-term ceasefire, negotiated by Ankara and Washington on Thursday.
The operation, launched by Turkey, forced the Kurdish militia of the US-backed Syrian Democratic Forces (SDF) to leave several areas in northern Syria, while the Turkish army and its local allies seized the border town of Ras al-Ayn.
In the meantime, the Syrian army also reclaimed several settlements, previously held by Kurdish militants after striking a deal with them.
The Arab League, the US and European countries al condemned the Turkish offensive, resulting in sanctions imposed by Washington and arms sales restrictions introduced by Berlin and Paris, among others.
President Recep Tayyip Erdogan, however, stated that his country would create a safe zone in Syria, promising to continue the fight against the SDF, which, according to Ankara, is affiliated with the Kurdistan Workers' Party (PKK) - a group, blacklisted as a terror organisation in Turkey.