MOSCOW: Russia claimed Friday to have killed several top commanders of the Islamic State group in an air strike in Syria, including the US-trained "minister of war" who has a $3 million bounty on his head, reports AFP.

"As a result of a precision air strike of the Russian air forces in the vicinity of Deir Ezzor city, a command post, communication centre and some 40 ISIS fighters have been killed," the Russian defence ministry said in a statement posted on Facebook.

"According to confirmed data, among the killed fighters are four influential field commanders including Deir Ezzor emir Abu Mohammed al-Shimali," the ministry said.

Gulmurod Khalimov, who is known as the IS group's minister of war and the highest-ranking defector from ex-Soviet Tajikistan, suffered a "fatal injury," it added.

Reports of Khalimov's death have surfaced before, and the Tajik interior ministry said it could not immediately confirm the claim. "We are working with our Russian colleagues to obtain reliable information," a spokesman told AFP.

But a spokesman for the Tajik security services, speaking to AFP, suggested that "this time around" he might have been killed.