Negotiations for the release of BBC journalist Alan Johnston have been held up because the Gaza clan holding him regards him as life insurance against reprisals by Hamas, The Jerusalem Post reported Friday, quoting sources close to Hamas.

Clan head Mumtaz Dughmush is refusing to release the correspondent for fear that Hamas would kill him and most of his clan members, the newspaper said.

Dughmush, known as Abu Muhammad, wants assurances from Hamas that he and his relatives would not be killed, the newspaper quoted the source close to Hamas as saying.

Since Saturday, dozens of Hamas gunmen have surrounded the area in Gaza City's Sabra neighbourhood where the clan lives, they said. Hamas has threatened to use force and storm the area if Johnston is not freed by Monday. A member of the clan, Munir Dughmush, was shot dead Wednesday by unknown gunmen in Gaza City, augmenting the family's fears.

"This man is a big thug," a source told the Post. "He is claiming to head a group calling itself the Army of Islam. In fact, this is just a group of murderers and thugs who want money and jobs."

A Hamas official charged that Mumtaz Dughmush was now close to Fatah official Mohammed Dahlan although he admitted he was close to Hamas in the past. But Dughmush had earlier denied any link to Dahlan and said he was actually very close to Hamas' leadership in Gaza, claiming he and the Islamic group had even planned to assassinate the Fatah strongman.

He said Dughmush had demanded US$2 million for Johnston, but "now he knows he's not going to get anything out of Hamas."

Hamas is determined to free Johnston, 45, to prove it is able to impose law and order in the volatile coastal salient. The Scottish journalist was captured at gunpoint near his Gaza City office on March 12. He has since become the longest-held foreigner in Gaza.