Russian fighter jets and Assad warplanes pounded the DAESH-held eastern province of Deir Ezzor with more than 50 air strikes, leading to the death of at least 36 people, Syrian Observatory for Human Rights (SOHR) reported, making it the heaviest attack in the region since the start of the war.
Russian jets pounded the terrorist-controlled province on Friday, by firing cruise missiles from warships deployed in the Caspian Sea, which marks the second time that warships have been used since the start of the Russian military campaign on September 30.
The strikes were launched following an assault staged by the terrorists to overrun an air base, where Assad troops are holed up just south of Deir Ezzor city.
In addition, Russian President Vladimir Putin vowed to retaliate after a bombing claimed by DAESH brought down a Russian airliner in Egypt last month, pledging to hunt down and "punish" those behind the downing which killed all 224 people on board.
Rami Abdel Rahman of the SOHR monitoring group stated that "at least 36 people were killed and dozens more injured in more than 70 raids carried out by Russian and Syrian planes against several districts in Deir Ezzor."
Abdel Rahman described the raids, which targeted several towns and cities in the province, including three oil fields, as "the worst bombardment of the region since the start of the uprising in 2011."
The province of Deir Ezzor is mainly governed by DAESH terrorists, with the exception of the military air base and a few other areas controlled by forces loyal to regime leader Bashar Assad.
The UN Security Council on Friday backed a French-drafted measure calling on member states to "take all necessary measures" to fight DAESH terrorists.
The resolution urges countries to "take all necessary measures, in compliance with international law... on the territory under the control of ISIL [DAESH]... in Syria and Iraq."
The call came one week following the Paris terror attacks claimed by DAESH, which lead to the death of 130 people in Paris, making it the worst terror attack on French soil.
Unidentified images circulated on the Internet of Syria-bound US missiles bearing the handwritten inscription "From Paris with love."
On Monday, the US-led coalition fighting DAESH reported that it had destroyed 116 fuel trucks used by the terrorist group in eastern Syria.
The terrorist organisation reportedly generates millions of dollars in revenue from oil fields under its control and the coalition has continuously targeted the oil infrastructure under the control of the group.
The Financial Times last month estimated in its investigation that the terrorist organisation reaps some $1.5 million per day from oil, based on the price of $45 a barrel.