The US-led coalition may have coordinated its Saturday's airstrike against the Syrian army with the Daesh terrorist group, Syrian President Bashar Assad's adviser Bouthaina Shaaban said Sunday.

MOSCOW (Sputnik) — The attacks by the coalition planes near the Deir ez-Zor airport were first reported by the Syrian army on Saturday. Later in the day, the Russian Defense Ministry confirmed the attacks saying they killed 62 servicemen and injured 100 more. The US Central Command said that Syrian forces were mistaken for Daesh fighters.

"The moment the American planes struck the Syrian army, the terrorists came from the same side that the Americans struck, and occupied the place [that] the Syrian army was in. So it was obvious to anyone in the field that there is an absolute coordination between the American planes who shelled the Syrian army and the terrorists who came in place of the Syrian army," Shaaban said in an interview with the RT channel.

The United States should be ashamed of killing Syrian troops, who have been defending Deir ez-Zor from Daesh attacks since 2014, in case it is committed to fighting terrorism in Syria, she stressed, adding that US airstrikes surprisingly stopped after Russia's warning signal instead of turning on Daesh militants who took over the Deir ez-Zor airport in the wake of the attack.

"I think, you know, it would be very strange if a country like the United States of America, who is supposed to be number one military power in the world, to make such a mistake" Shaaban said.

Syria has been mired in civil war since 2011, with government forces fighting numerous opposition factions and extremist groups, including Daesh, which is outlawed in many countries, including Russia. The government-held city of Deir Ez-Zor has been under siege from IS since July 2014.

The US-led coalition has been carrying out anti-Daesh strikes since September 2014 without Syrian government consent.