Syrian and Russian jets have attacked Daesh positions in Dayr al-Zawr following a US bombing which killed 62 government troops in the eastern town and allowed the Takfiri group to make gains.
Lebanon-based al-Mayadeen TV said the attacks on Monday wiped out several Daesh positions and inflicted heavy losses. Two arms depots and several oil tankers of the Takfiri group were destroyed in the airstrikes.
Daesh controls large parts of Dayr al-Zawr city as well as most of the province for which it is the capital. The terrorist group chiefly relies on oil fields in the province to fund its atrocious war in Syria.
The Syrian army has been fighting it out against Daesh for the control of a key military airbase there. Syrian troops came under heavy US aerial bombardment on Saturday, which Damascus says was premeditated.
Dayr al-Zawr has been effectively under a Takfiri siege since early 2015 but the terrorists have suffered major setbacks over the past few months during which the Syrian army has liberated several areas.
On Sunday, a senior adviser to Syrian President Bashar al-Assad said Damascus believed the US airstrike in Dayr al-Zawr was "intentional."
"None of the facts on the ground show that what happened was a mistake or a coincidence," Buthaina Shaaban told AFP.
The Pentagon has said the attack was carried out mistakenly even though it allowed Daesh to take over some parts of the region.
The Takfiri group said on Sunday it shot down a Syrian warplane near the city. State media confirmed a plane had been shot down and its pilot killed, but did not say who was responsible.
Russia said the airstrikes "if they, as we hope, were not taken on orders from Washington -- fall between criminal negligence and direct pandering to Daesh terrorists."
Russian counterpart Vitaly Churkin called the strike a "bad omen" for the US-Russia deal to halt Syria's war.
On Monday, a seven-day ceasefire declared by the Syrian army expired at midnight, with no immediate announcement of its extension.
The "regime of calm" was announced on Sept. 12 following a ceasefire brokered by the United States and Russia.
The government has accused foreign-backed militants of numerous violations of the ceasefire, the second this year.
Turkish warplanes bombed northern Syria, the Turkish military said in a statement on Monday, claiming that targets used by Daesh as shelter, ammunition store and military headquarters were hit in the airstrike.