DUBAI - Kidnappers holding five Britons seized in Iraq in May threatened to kill one hostage in 10 days as a "first warning" unless Britain withdraws from Iraq, in a video aired by Al Arabiya television on Tuesday.

The video, dated November 18, showed a hostage sitting on the floor flanked my masked gunmen pointing assault rifles at him.

A statement said that if Britain failed to leave Iraq within 10 days after it was broadcast, "this hostage will be killed as a first warning, which would be followed with details that you would not want to know".

Britain has not disclosed the names of the five Britons -- a computer consultant and his four bodyguards -- who were snatched from a Finance Ministry data processing centre by gunmen wearing police commando uniforms in May.

"My name is Jason. Today is November 18. I have been here now 173 days and I feel we've been forgotten," said the hostage on the video as he sat in front of a banner of the Shi'ite Islamic Resistance in Iraq.

Britain condemned the video.

"No matter what the cause, hostage taking can never be justified. We again call on those holding the men to release them unconditionally," a spokesman said in London.

"We condemn the publication of this video which serves only to add to the distress of the men's family and friends."

Iraqi officials have said they suspect Mehdi Army militiamen loyal to Shi'ite cleric Moqtada al-Sadr of carrying out the kidnapping, possibly in retaliation for the killing of a militia leader in southern Iraq by British-backed Iraqi special forces.

A U.S. military official said in September that rogue elements of the Mehdi Army were behind the abductions.

"They (hostages) have confessed and given details of plans in which they came to loot our wealth under the fake cover of being consultants at the Finance Ministry. We will show details of their confessions later," the group said on the video.

Arabiya did not say how it obtained the video, but an official at the Dubai-based satellite television channel said the station received an anonymous call giving a location where the tape could be found.

Most kidnappings of Western hostages carried out in Iraq since the 2003 U.S.-led invasion have been carried out by Sunni insurgents groups, including al Qaeda.