Vittorio Arrigoni, a 36 year old Italian pro-Palestinian activist, has been found murdered in the Gaza Strip.
Mr Arrigoni was found hanged in a house by police in the Hamas-run region. He was kidnapped and killed by a group known as Salafists.
The Salafists say that Hamas, which wants to destroy the state of Israel and has killed opposition figures in the past, is too moderate. The leader of the Salafists, Sheikh Maqdasi, was arrested last month by the Hamas authorities.
The group posted a video on YouTube which showed Mr Arrigoni blindfolded with black tape. He also bore visible injuries indicating he had been beaten. The video proclaimed, "The Italian hostage entered our land only to spread corruption."
The Salafists said that Mr Arrigoni would be killed by 14:00 GMT today if their leader and several others were not released. There is as yet no indication as to why Mr Arrigoni was killed before the given deadline.
The Italian government has condemned the killing, while a spokesman for the Hamas interior ministry said the murder was a "heinous crime which has nothing to do with our values, our religion, our customs and traditions".
The International Solidarity Movement, the pro-Palestinian organisation of which Mr Arrigoni was a part, said, The International Solidarity Movement is shocked and deeply saddened by the killing of our friend and colleague Vittorio Arrigoni. Vit was an inspiring activist and generous soul. Please keep his family and friends in your thoughts."