A roadside bomb wounded five Italian military members on Sunday in northern Iraq as they returned from a mission where they helped Iraqi troops to battle ISIS.
The Italian Defence Ministry said three of the wounded were in very serious conditions.
Adm Fabio Agostini said the five – three from the navy and two army soldiers – were part of a special forces team.
Iraqi soldiers were also wounded in the blast, Adm Agostini told Italian Rai state TV, but he did not say how many.
An Iraqi security official said the bomb exploded next to the Italians' vehicle as they were travelling just outside Kirkuk.
US military helicopters flew the soldiers to a hospital in Baghdad.
One had his leg amputated while another suffered serious internal wounds, Gen Nicola Lanza de Cristoforis told state TV.
Iraq declared victory against ISIS two years ago but the group continues insurgent-style attacks, particularly in the north.
Italy has more than 800 regular soldiers and about 80 special forces soldiers in Iraq.