"As for the latest developments (concerning the actions of the US-led coalition against the ISIL terrorist group), we posed a question to (US Secretary of State John) Kerry," he said on Monday, RT reported.

"We think it counterproductive to publicly announce that aviation will deliver air strikes to protect groups of the so-called moderate opposition. Such plans raise many questions. (These actions) will hamper anti-terrorist efforts."

On Sunday, US officials said that Washington had decided to allow air strikes to defend US-trained Syrian militants from any attacks, including those made by the forces of Syrian President Bashar Assad.