WASHINGTON (AFP) - A top Islamic State in Iraq and Syria (ISIS) group commander known as "Omar the Chechen" is dead after suffering injuries in a US-led coalition strike in north-eastern Syria, the Pentagon confirmed on Monday (March 14).

The announcement would appear to clear up the fate of the notorious Omar al-Shishani, a week after a US official said the most-wanted militant had been targeted in a March 4 attack on the terrorist's convoy.

"We believe he subsequently died of his injuries," Navy Captain Jeff Davis, a Pentagon spokesman, told AFP.

On Sunday, the Syrian Observatory for Human Rights monitoring group said Shishani had been "clinically dead" for several days.

Shishani - the nom de guerre of Tarkhan Batirashvili - was one of the IS leaders most wanted by Washington, which put a US$5 million (S$6.88 million) bounty on his head.