A senior Islamic State militant who the US claimed to have killed in an air strike is badly wounded but still alive, a monitoring group said.

Abu Omar al-Shishani was targeted near the town of al-Shadadi in Syria last Friday, US officials said on Tuesday (8 February). Also known as Omar the Chechen, the militant is described as the group's minister of war.

However, Rami Abdulrahman, director of the Syrian Observatory for Human Rights which monitors the conflict, said that al-Shishani had been badly injured in the airstrike but not killed, and had been taken to IS' Syrian centre of operations Raqqa for treatment.

"He did not die," Abdulrahman told Reuters. IBTimes UK is unable to verify the claim independelty.

Born in Georgia in 1986, al-Shishani joined IS (Isis/Daesh) in 2013, and is believed to be one of the senior figures in the terror group and a confidante of its leader Abu Bakr al-Baghdadi.

He is believed to have been sent to the north-eastern town of Shaddadi to bolster IS fighters, who are under increasing pressure on the ground from Syrian and Kurdish forces.

A statement issued by the US Department of Defense on Tuesday said that officials were "still assessing the results" of the operation on 4 March. An unammed senior defence official told AP that the militant was likely killed with 12 others following multiple waves of strikes involving manned and unmanned drones.