After a nine-day silence the kidnappers of two journalists seized at gunpoint in Gaza issued a video of the hostages yesterday and a ransom note demanding that the US release Muslims held in American jails.

The previously unknown Holy Jihad Brigades released the footage of the US Fox News team, the American Steve Centanni, 60, and his cameraman, the New Zealander Olaf Wiig, 36, in which they appear relaxed and say that they have been well treated.

But a two-page letter in Arabic accompanying the video carries an implicit threat in that it demands that the Muslim prisoners must be released within 72 hours in order to win the journalists’ freedom. It does not say what will happen if the demand is not met.

The US State Department last night rejected the demand and said that the journalists must be released unconditionally. Fox News also called for their immediate release.

Diplomats working to free the journalists had become increasingly concerned about the fate of the pair, kidnapped in a well-planned operation, because no group had claimed responsibility.

The journalists had already been held in captivity longer than any of the 26 foreigners kidnapped in Gaza over the past two years.

Most captives are freed after 24 or 48 hours by their amateurish abductors who are invariably pressing local grievances.

President Bush and Condoleezza Rice, the US Secretary of State, are understood to have contacted Mahmoud Abbas, the Palestinian President, directly, asking him to appeal for their freedom.

Ismail Haniya, the Prime Minister of the Hamas Government, pleaded that the “guests” be released. American and British journalists were warned two days ago of “credible threats” of risk of further kidnaps in Gaza.

The journalists were abducted after their vehicle was boxed in by trucks in Gaza city centre on August 14. A 90-second tape showing the two men sitting cross-legged against a black background was released yesterday to al-Jazeera’s agent in Gaza.

They are wearing jogging suits, different from the clothing they wore when they were seized, and say that they are being given food, water and access to showers and toilets.

“I just wanted to let you know I’m here and alive,” the Washington-based Mr Centanni says. “I want to give my love to my family and friends and ask you to do anything you can to help get us out of here.” Mr Wiig asks his wife, Anita McNaught, a former BBC broadcaster who is in Gaza working to secure his release, to exert any political pressure she can.

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