Amaq, a news outlet affiliated to ISIS, said in an online statement released on Sunday that the jet came down in Jebel Tharda area, near the Deir Ezzor military air base.
The air base, along with some other government-held districts, has been besieged by ISIS over the past year.
The Syrian army has confirmed the downing of the warplane, saying it had been on a mission against ISIS when it was shot down.
The undated photo shows a Syrian MiG-23 fighter jet. (Photo by AFP)
On Saturday two US F-16 and two A-10 jets warplanes entered the Syrian airspace from Iraq and conducted at least four airstrikes against Syrian army positions near Deir Ezzor airport. Over 60 Syrian soldiers were killed and a hundred others were injured.
The Pentagon later said in a statement that the attack had been launched against wrong targets and that they "believed they were striking a ISIS" position.
The deadly attack drew strong condemnation both from the Syrian government and Russia. Moscow began airstrikes against ISIS in Syria in September 2015 upon a request from Damascus.
Syria’s Foreign Ministry has called on the UN Security Council to condemn the US airstrike.
Russia’s Foreign Ministry has said the US airstrike was “on the boundary between criminal negligence and direct connivance” with the Takfiri terrorists.
Syrian soldiers walk in an area in the government-held part of Aleppo, northwestern Syria, September 16, 2016. (Photo by AFP)
It said the incident was a result of Washington’s “stubborn refusal” to cooperate with Moscow in fighting ISIS, Jabhat Fateh al-Sham, al-Qaeda’s Syrian branch formerly known as al-Nusra Front, and “other terrorist groups.”
The deadly US airstrike could threaten a recent deal between Moscow and Washington on an end to the conflict in Syria. Russia and the United States agreed on the milestone deal in the Swiss city of Geneva on September 9.
The deal, which went into effect on September 12 and was initially agreed to last seven days, calls for increased humanitarian aid for those trapped inside the embattled northwestern city of Aleppo.
Under the terms of the ceasefire agreement, Russian and US aircraft are to launch joint airstrikes and pound the positions of Takfiri terrorists in Syria.
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