IS group shot down a Syrian military plane in the eastern Syrian city of Deir al-Zor, the Islamic State-affiliated news agency Amaq said on Sunday.
"A Syrian warplane belonging to the Syrian regime was brought down when targeted by fighters from the Islamic State in the city of Deir al-Zor," Amaq said in an online statement.
The Syrian Observatory for Human Rights, which monitors the Syrian conflict now in its sixth year, said the pilot of the MiG Syrian warplane was killed.
The Observatory said the plane came down in the Jebel Tharda area which overlooks the government's Deir al Zor military airport.
Jebel Tharda is where on Saturday U.S.-led coalition air strikes reportedly killed dozens of Syrian soldiers, endangering a U.S.-Russian brokered ceasefire and prompting an emergency U.N. Security Council meeting as tensions between Moscow and Washington escalated.
The city's airport and some government-held districts have been entirely surrounded by Islamic State since last year, with the airport providing the only external access.
Intense air strikes over the past 24 hours have hit Islamic State controlled areas near Deir al Zor city, the Observatory and Syrian state media said.