TOP-SECRET files detailing interrogations of more than 700 terrorism suspects at the Guantanamo Bay detention camp have been obtained by whistle-blowing website WikiLeaks.

Thousands of pages of sensitive documents about nine years of interviews in which extremists admit to plotting attacks against the West have apparently been shown to two newspapers.

According to the files, written by officials at the controversial base, al Qaeda terrorists have threatened to unleash a “nuclear hellstorm” if Osama bin Laden is caught or killed.

The documents detail the background to the capture of each of the 780 people who have passed through the Cuban facility, along with their medical condition and the information they have provided during interrogations.

Around 220 of those detained are assessed to be dangerous international terrorists, while around 380 are judged to be lower-level foot-soldiers.

At least a further 150 people including innocent Afghans and Pakistanis, were held and assessed at the US camp, but later released due to lack of evidence, according to the files.

They show the Americans have seized more than 100 al Qaeda members. The most senior is Khalid Sheikh Mohammed, the terrorist group’s operational commander who is accused of masterminding the 9/11 attacks. According to one of the newspapers, his file discloses he was plotting attacks in Asia, Africa, America and Britain.

It concludes: “Detainee had numerous plots and plans for operations targeting the US, its allies, and its interests worldwide. Targeting priorities were determined by initially assessing those that would have the greatest economic impact, and secondly which would awaken people politically.”

The files are also said to disclose that a senior al Qaeda commander claimed that a nuclear bomb is hidden in Europe and will be detonated if Bin Laden is caught or killed.

Sheikh Mohammed told interrogators that the extremist group would unleash a “nuclear hellstorm”.

The alleged 9/11 plotter also said al Qaeda was trying to recruit ground-staff at Heathrow to help them target the world’s busiest airport.

A plot to put cyanide in the air-conditioning units of public buildings across America was also exposed.

Guantanamo Bay was opened by the American government in January 2002 and about 180 people are still held there.

The facility was subject to international controversy after torture-style techniques including water-boarding, stress positions and sleep deprivation were approved to be used on prisoners during the Bush administration.

A spokesman for Amnesty International UK said: “We haven’t yet been through these latest disclosures in detail but they appear to back up many of the things we’ve said about Guantanamo being a travesty of justice.

“It’s important to remember that this is far from over – there are 172 prisoners still at the camp and instead of fair trials they are set to be put before unfair military commissions or even remain detained without any trial at all.

“In the case of Shaker Aamer and former UK detainees like Binyam Mohamed, it will be important that the forthcoming Gibson inquiry into the UK’s alleged involvement in torture fully examines the WikiLeaks documents.”