A You Tube clip the group posted on Thursday said the man they were holding, Vittorio Arrigoni, would be killed on Friday at 5 p.m. local time (1400 GMT) unless Hamas releases Hesham al-Sa`eedni, whom it detained last month.
"If our demands are not met within 30 hours starting from 11 a.m. of 14.4.2011 the captive will be executed when the period is over," a text on the video clip said.
Arrigoni, an Italian pacifist and blogger, has lived in the Gaza Strip for some time. He was shown blindfolded with blood around his right eye and a hand can be seen pulling his head up by his hair to face the camera.
A spokesman for the Hamas interior ministry in Gaza City said it was investigating the abduction.
It was unclear when Arrigoni was kidnapped or where he was being held, but an Italian diplomat who serves in the region confirmed to Reuters he had been abducted.
The Arabic text that accompanied the footage of Arrigoni also said "the Italian hostage entered our land only to spread corruption" and it described Italy as "the infidel state".
Arrigoni is the first foreign national to be abducted in the Gaza Strip since BBC journalist Alan Johnston, who was held for 114 days by an al Qaeda-inspired clan group named the Army of Islam. He was released in 2007.
Arrigoni came to the Gaza Strip on a boat bringing humanitarian supplies in 2008 that Israel, which enforces a blockade on the tiny coastal territory, allowed into Gaza port.
Hamas, which has in the past denied any al Qaeda presence in Gaza, has been trying to keep other Islamist groups in check following a devastating Israeli military offensive in 2009. (S008/K004)
Editor: Kunto Wibisono
Copyright © ANTARA 2011
