GAZA CITY (CNN) -- Clad in what appeared to be an explosive vest, kidnapped BBC correspondent Alan Johnston warned Sunday that his captors would turn their hideout into a "death zone" if any rescue attempt is made.
"I do appeal to the Hamas movement and the British government not -- not -- to resort to the tactics of force in an effort to end this," Johnston said in a video clip released by his captors and posted on Islamic militant Web sites.
Johnston, the BBC correspondent in Gaza, was kidnapped March 12 by a group calling itself the Army of Islam.
The Palestinian Islamic party Hamas, which wrested control of Gaza from its Fatah rivals two weeks ago, has pledged to seek his release.
Sunday's video showed Johnston standing before a black background, wearing a long-sleeved red shirt beneath what appeared to be an explosive vest.
"My captors tell me that very promising negotiations were ruined when the Hamas movement and the British government decided to press for a military solution to this kidnapping, and the situation is now very serious," he said.
Johnston urged British and Palestinian officials to resume negotiations, adding, "They're willing to turn the hideout into what they described as a 'death zone' if there's an attempt to free me by force."
There was no immediate reaction to the scene from Hamas or the British Foreign Office, but the BBC condemned the video.
"It is very distressing for Alan's family and colleagues to see him being threatened in this way," the network said in a statement issued early Monday. "We ask those holding Alan to avoid him being harmed by releasing him immediately. We are keeping his family fully informed and offering them our continued support."
Johnston's captors are demanding the release of a Jordanian-born Muslim cleric held in Britain on suspicion of links to terrorist organizations, along with other prisoners held by what they call infidel states.
There was no immediate reaction to the video from the BBC, Hamas or the British Foreign Office.
Johnston, 45, joined the BBC World Service in 1981. In a video released in early June, he said he was being treated well and was in good health.
He is one of 15 journalists abducted in Gaza since 2004, according to the New York-based Committee to Protect Journalists. All the others were released unharmed, usually within days of their abductions.
Little is know about the Army of Islam, which also claimed to have taken part in the 2006 kidnapping of Israeli army Cpl. Gilad Shalit.
Despite Israeli incursions and airstrikes into Gaza aimed at freeing him, Shalit is believed to remain in captivity.
