Abu Omar al-Shishani, who the Pentagon described as Islamic State's "minister of war", was killed in combat in the Iraqi city of Shirqat, south of Mosul, a news agency that supports the militant group said on Wednesday, July 13, according to Reuters.

The Pentagon said in March that Shishani had likely been killed in a U.S. air strike in Syria, but this was the first time the group appeared to confirm his death.

Reuters could not independently verify the statement from Amaq news agency, which Islamic State regularly uses to issue reports and which denied Shishani's death after the Pentagon's comments in March.

Islamic State supporters exchanged notes of praise and condolence on social media, including pictures of the ginger-bearded fighter, and pledged to launch a fresh offensive in his honor.

Officials at the Pentagon said they were aware of Wednesday's report but could not confirm or deny it.

Hisham al-Hashimi, a Baghdad-based security expert who advises the Iraqi government, said a source in Shirqat confirmed Shishani had been killed there along with several other militants.

Iraqi forces are advancing towards Mosul, the largest city still under the control of Islamic State. They have mostly surrounded Shirqat, 250 km (160 miles) north of Baghdad, and last week retook a major air base from the militants to use in the main push on Mosul, 60 km further north.