"If previously we had suspicions that Fatah al-Sham Front (formerly known as al-Nusra Front) is protected this way, now, after Saturday airstrikes on the Syrian army we come to a really terrifying conclusion for the entire world: The White House is defending the ISIL," Russian Foreign Ministry spokeswoman Maria Zakharova said, Russia 24 reported.

"We demand a full and detailed explanation from Washington. That explanation must be given at the UN Security Council," Zakharova added.

The Foreign Ministry has demanded full and detailed explanation from Washington over the incident in Deir Ezzor, in which 62 Syrian troops were killed and over 100 injured.

Moscow stressed that it is concerned by the US airstrike targeting the Syrian army units which had been destroying the ISIS militants.

The ministry added that the Russian side had never been notified of US plans to carry out bombings in the Deir Ezzor area.

The Russian Foreign Ministry stressed US air strikes against Syrian government forces jeopardize the Syrian ceasefire deal reached between Moscow and Washington on September 9.

Earlier on Saturday Russia's Defense Ministry said that four strikes against Syrian positions had been delivered by US-led coalition aircraft, including two F-16 jet fighters and two A-10 support aircraft.

The Syrian military called the bombing a "serious and blatant aggression" against Syrian forces, and said it was "conclusive evidence" that the US and its allies support ISIL militants.

US Central Command later issued a statement, saying that the US-led coalition would not intentionally strike a known Syrian military unit. It promised to look into the incident, FNA reported.

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