The Pentagon said Tuesday that it could not confirm a report that a former Guantanamo Bay detainee carried out a suicide attack on behalf of ISIS in Mosul, Iraq this week.
The BBC reported that ISIS claimed responsibility for the attack and praised Abu Zakariya al-Britani, a British suicide bomber, for exploding a vehicle full of explosives near Mosul, where Iraqi forces are battling ISIS fighters for control of the city.
Pentagon spokesman Maj. Ben Sakrisson told Fox News in an email that a person known as Jamal Malik al-Harith was held at Guantanamo Bay between February 2002 and March 2004, when he was released to the United Kingdom.
The BBC report stated that al-Britani, born Ronald Fiddler, also went by the similar-sounding Jamul-Uddin al-Harith.
"We cannot confirm his death, as the occurrence of the same name does not necessarily equate to this being the same individual," Sakrisson told Fox in the email.
Similarly, a U.S. defense official told Fox News that whether al-Britani spent time at Guantanamo Bay was "very much in doubt."
The BBC reported that al-Britani crossed into Syria from Turkey in April 2014 to join ISIS. His wife told the Daily Mirror newspaper that she and her five children unsuccessfully went to Syria to persuade him to return to Britain.
The British government estimates that 850 people described as "national security concerns" have traveled to become fighters in the Middle East. Just under half that number are believed to have returned to the U.K.
Fox News' Lucas Tomlinson contributed to this report.