GAZA — A radical, Al Qaeda-inspired Islamic group in Gaza said Thursday that it had kidnapped an Italian citizen in the Palestinian territory and threatened to execute him unless Hamas, which rules Gaza, released the group’s imprisoned leader by 5 p.m. on Friday.

But early Friday morning, Hamas officials announced that the body of the Italian man, a pro-Palestinian activist, had been found.

Palestinian officials said the Hamas police had stormed a house where they thought the man was being held and, after a clash with his abductors, found his body. The police said he had been hanged, The Associated Press reported.

The radical group, known as Tawhid and Jihad, had released a video on Thursday that it said showed the hostage. The group described the captive as “Victor, an Italian journalist” and called for the release of its supporters and other global jihadists.