A British Islamic State fighter has reportedly carried out a suicide bombing near Mosul.
The bomber - named by the group as Abu Zakariya al-Britani - is said to have detonated an explosives-filled vehicle in a village to the south of the Iraqi city.
The Britani suffix has been used regularly for militants from the UK.
There has been no official confirmation of the death, and it is unclear when the attack took place.
A Foreign Office spokeswoman said: "The UK has advised for some time against all travel to Syria, and against all travel to large parts of Iraq.
"As all UK consular services are suspended in Syria and greatly limited in Iraq, it is extremely difficult to confirm the whereabouts and status of British Nationals in these areas."
Around 850 individuals of national security concern have travelled to join the conflict, according to figures published by the Government last year.
Of those, just under half have returned to the UK and approximately 15% are dead.