Syria State television said jets from a US-led international coalition raided the government-held Qusur district of Deir ez-Zor city and killed 14 civilians and wounded 32 others.
In the meantime, the Britain-based Syrian Observatory for Human Rights said a Monday night airstrike killed 22, adding that the identity of the warplanes was not immediately clear, Associated Press reported.
However, US military spokesman Col. Ryan Dillon denied the report in a tweet saying that the coalition has not bombed the city, of which Daesh currently controls a small part, since September.
Last year, the US-led coalition bombed Syrian army positions near the city of Deir ez-Zor killing at least 62 Syrian soldiers and leaving more than a 100 wounded.
The US-backed coalition has been conducting air strikes against Daesh in support of the Syrian Democratic Forces (SDF) alliance of Kurdish and Arab militias to the east of Deir ez-Zor across the Euphrates.
Damascus on several occasions protested the US-led coalition strikes, calling their presence in the war-torn country illegal.