BAGHDAD — Captors holding five Britons demanded Tuesday that Britain pull all its forces from Iraq, posting a videotape showing a bearded, haggard-looking victim more than six months after the group was kidnapped.

The hostage, speaking clearly with a British accent, identified himself as "Jason" and gave the date as more than two weeks ago. He sat under a sign in Arabic identifying the captors as "The Islamic Shiite Resistance in Iraq."

"My name is Jason. Today is November 18," he said. "I have been here now for 173 days, and I feel we have been forgotten."

A written statement featured on the video, aired by Al-Arabiya television, accused Britain of plundering the wealth of Iraq and demanded that British troops leave within 10 days. It did not say what would happen if the deadline was not met nor when the countdown begins.

Britain's Foreign Office condemned the broadcast, saying it "serves only to add to the distress of the men's families and friends." British officials have not released the names of the kidnapped men and have requested their identities not be disclosed by the media.

The kidnapping took place May 29, when about 40 gunmen in police uniforms and driving vehicles used by Iraqi security forces grabbed the four security contractors and a computer consultant from an Iraqi Finance Ministry compound. Suspicion has fallen on Shiite splinter groups that the United States believes have been trained and funded by Iran.

The video was posted as Britain prepares to hand over security control of oil-rich Basra province — the last of four regions of southern Iraq it occupied after the 2003 invasion — to the Iraqis in mid-December.

British troops withdrew in September from their last base in Basra city to an airport garrison on the outskirts, and half the 5,000 British troops in Iraq are due to go home by the spring.

One expert suggested a motivation for the rare broadcast of a video by a purported Shiite group could be to project the handover as a victory for the militia factions battling for control of the area.

"They're aware of countries who are already pulling their forces out," said Ben Venzke, the head of IntelCenter, a Virginia-based firm that tracks terrorist activity. "It can sometimes allow them to tie events to it and hold it out as a victory."