"A gang of terrorists has taken advantage of the fact that a de-escalation zone had been established in Idlib and entrenched their positions there, they have increased their ranks and begun raids against the civilian population of Syria, attacks on the Russian bases … We cannot but react to such aggression," Syromolotov said.
The deputy foreign minister also explained the details behind preparations for a possible operation in Syria's Idlib de-escalation zone.
"As regards the parameters of counter-terrorist operations in Idlib, such operations are generally planned carefully and secretly with the participation of all parties, neither the military nor diplomats talk about such things publicly," he said.
Syromolotov noted that at the same time, all humanitarian aspects are being taken into consideration, including efforts to "reduce the damage to civilians and infrastructure."
The province of Idlib remains the last terrorist stronghold in the country and is also one of Syria's de-escalation zones. Syrian President Bashar Assad earlier stressed that the liberation of the province was foremost among the Syrian military's priorities.
Chemical Weapons in Syria
The official noted that the terrorists have found opportunities to produce chemical weapons in Syria.
"Over the years of military operations in Syria, as well as in neighboring Iraq, information has been received about the capture of scientific and technical documentation on the production of chemical weapons (for example, in a specialized library in the Iraqi city of Mosul) and chemical enterprises with the necessary equipment, involvement of civil and military chemical specialists in the synthesis of chemical warfare agents by militants," Syromolotov said.
At the same time, the deputy minister noted that there has been "a certain material and technical assistance from abroad."
According to the diplomat, there are numerous reports about preparations for chemical weapons incidents.
"Real-time data on the preparation of new chemical weapons incidents by extremists in Syria are constantly coming in," Syromolotov said, adding that the Syrian side "regularly submits very specific information on the matter to the UN Security Council and the Organization for the Prohibition of Chemical Weapons."
He noted that the Syrian mission to the UN had officially informed the UN Security Council Committee 1540 on August 17 about the delivery of several containers of chlorine to a militant camp in Idlib province.
Russia-US Anti-Terror Working Group
Moscow and Washington are discussing parameters for re-establishing a working group on anti-terror as discussed by Russian President Vladimir Putin and his US counterpart Donald Trump during the summit in Helsinki, Syromolotov said.
"At the moment, the relevant ministries of Russia and the United States, contacts between which have never ceased, are specifying the relevant parameters… It would be premature to anticipate the results now. We have firmly advocated a non-politicized and equal cooperation with the US in the area of anti-terror that is based on respecting mutual interests," he noted.
Turkey's Reaction to Operation
Ankara, when addressing the situation in the region, called on Russia to refrain from a massive use of force in Syria's Idlib province, Syromolotov told Sputnik.
"The Turkish side backs our position on the need to eliminate terrorists in the Idlib de-escalation zone with minimum impact on the civilian population … At the same time, the Turkish side asks us in bilateral contacts to refrain from a massive use of force in order to solve the Idlib problem," he said.
Turkish President Rejep Tayyip Erdogan earlier claimed that his country hoped to prevent "disproportionate" measures by the Syrian government against militants in Idlib, stating that such an offensive would lead to a massacre.