Radical group threatens to execute kidnapped US journalist today

Internal links

War on terror has just begun, declares Bush

San Francisco airport evacuated as explosive found on passenger's shoe

Aid worker known as the 'Tartan Taliban' is released without charge

Blair rounds on 'unfair' press over Cuba camp

Natasha Walter: To be anti-Bush is not anti-American

Leading article: President Bush has earned the praise of America but not the trust of the world

Kidnappers holding an American journalist hostage in Pakistan threatened last night to execute him today.

An e-mail sent to various news organisations by his kidnappers said that his safety would be secured only if Pakistani prisoners who were captured during fighting in Afghanistan were released.

Daniel Pearl, a reporter for the Wall Street Journal who is based in Bombay, went missing a week ago in Karachi after arranging to meet a radical Islamic group he believed was linked to the alleged "shoe-bomber", Richard Reid.

An e-mail sent this week by a group calling itself the "National Movement for the Restoration of Pakistani Sovereignty", included photographs of Mr Pearl, aged 38, with a gun held to his head and claimed he was a CIA agent – an allegation denied by his employers and the agency.

The latest e-mail, sent yesterday to the Wall Street Journal, CNN and The New York Times among others, accuses Mr Pearl of being a spy for Israel. It also warns other American journalists in Pakistan to leave the country in three days.

"We have interrogated Mr D Pearl and have come to the conclusion that, contrary to what we thought earlier, he is not working for the CIA. In fact, he is working for Mossad, therefore we will execute him within 24 hours unless America fulfils our demands," it says.

The latest e-mail comes as police in Islamabad said they had detained Mubarak Ali Gilani, the leader of Jamaat al-Fuqra, and considered him a prime suspect in the case. Investigators have said Mr Pearl met Mr Gilani before he disappeared, and police have detained and questioned a number of people close to the religious leader and al-Fuqra.

The Wall Street Journal said in a statement: "Mr Pearl, a US citizen born in the US and a working journalist all of his adult life, is not an agent of any government or agency. He is a reporter for us – nothing more or less. He cannot affect the policy of the US or Pakistani government. Nor can we."

At the time of his kidnapping, Mr Pearl was looking at possible links between Jamaat al-Fuqra and Mr Reid, who is being held in the US where he faces charges of trying to destroy an airliner. The suspect, a Briton, is believed to have travelled to Pakistan shortly before he boarded the plane in Paris that was bound for Miami.

In their first e-mail, the kidnappers said Mr Pearl was being held in "inhumane" conditions in protest against the treatment of the 158 Taliban and al-Qa'ida fighters who are being held by the Americans at the Guantanamo Bay naval base on Cuba.