Abu Usama al-Irelandi, born Terence Kelly, was said to have detonated an explosive-laden vehicle in northern Iraq
Ireland's foreign ministry is investigating reports that an Irish citizen died in a suicide attack near the Iraqi city of Mosul, a spokesman said on Saturday.
The ISIL’s al-Jazeerah Province in northern Iraq on Friday said Abu Usama al-Irelandi detonated an explosive-laden vehicle, killing and wounding dozens, the SITE Intelligence Group, a US company that monitors Islamist websites, reported.
Abu Usama is a pseudonym used by Irish ISIL sympathiser Terence Kelly. Pictures posted by ISIL sympathisers on Twitter showed a man resembling Kelly posing with a machine gun in front of an armoured car.
Tal Afar is around 80 kilometres west of Mosul. Reuters could not immediately confirm the report.
Ireland's Foreign Ministry said it was looking into reports of an Irish citizen's death, but declined to comment on their identity.
"The department is aware of media reports concerning an Irish citizen in Iraq and is seeking to clarify the situation," the Irish Foreign Ministry spokesman said.
Kelly was brought up Catholic in central Dublin and converted to Islam in his early 30s in Saudi Arabia, where he worked as a nurse for three years, converting in prison after he was arrested for illegally brewing alcohol. He also used the pseudonym Khalid Kelly.
Kelly repeatedly praised al Qaeda and Osama Bin Laden in interviews with the Irish media and was arrested in 2011 for making threats against US President Barack Obama ahead of his visit to Ireland.
He travelled to Pakistan and later told interviewers that he had trained with militants there.
Iraqi troops on Saturday advanced towards Mosul, battling for the last town left between them and the ISIL stronghold to the north, which was already under assault from special forces inside its eastern districts.
Recapturing Mosul would effectively crush the Iraqi half of a self-proclaimed caliphate declared by ISIL leader Abu Bakr al-Baghdadi from the pulpit of a Mosul mosque two years ago. His Islamist group also controls large parts of east Syria.