Bush warns of al-Qaeda threat

Bin Laden had appeared frail in previous video tapes

US President George W Bush says an audio tape allegedly featuring the voice of al-Qaeda leader Osama Bin Laden has put the "world on notice".

The tape is being taken seriously

"Whoever put this tape out has put the world on notice yet again that we're at war and that we need to take these messages very seriously and we will," he said.

"It doesn't matter how long it takes, we'll find them and bring them to justice."

His comments follow agreement from experts from across the world that the voice, heard praising recent attacks on Western targets, is that of the wanted Saudi dissident.

Attacks threatened

The list of killings on the tape, referring to the bombings in Bali and Yemen, shootings in Kuwait and the takeover of a Moscow theatre by Chechen rebels would mean that Bin Laden was still alive last month.

[If authentic] it is an effort to show members of al-Qaeda that top leadership is still around

US official

It was broadcast by Arabic television station al-Jazeera.

The BBC's Security Correspondent Frank Gardner says intelligence analysts believe the message was intended as a morale boost for al-Qaeda and its supporters, but Saudi individuals familiar with Bin Laden's thinking say the tape contains a clear warning to Britain and other countries.

They believe Britain's firm support for Washington's policy could now make it a priority target for al-Qaeda.

US intelligence agency experts were still analysing the tape using specialist equipment, and Mr Bush said that he would speak to them about whether they were in full agreement as to the identity of the speaker.

But officials in Washington have already said they believe it was Bin Laden who made the recording, which goes on to threaten more attacks against the US and its allies.

One US official said: "It's probably his voice," but added: "It cannot be said with absolute certainty."

Mr Bush said that the US and its allies were continuing to make "great progress" in the war on terror and that extremist networks were being dismantled.

The tape does not convince me

Tim Renfro, USA

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Possible sickness

Experts are believed to be scrutinising the tone of the voice on the audio tape as well as inflection patterns and word usage.

The voice praised the bomb attack in Bali

George Michael, a language analyst in the US who has worked on previous Bin Laden tapes, told the BBC's Today programme he would be prepared to swear in court that the statement was made by the al-Qaeda leader.

There were some differences to previous Bin Laden messages, in particular sentences were shorter and more sharply enunciated, as if the speaker had to catch his breath to talk, Mr Michael said.

Bin Laden is said to have kidney problems and be in need of dialysis.

Japanese voice expert Matsumi Suzuki agreed with Mr Michael that the voice on the tape was Bin Laden's, Kyodo news agency reported.

Mr Suzuki said his analysis showed the message had been recorded in a room with a tight security system and that the speaker was hoarse, suggesting he was unwell.

True to style

Osama Bin Laden's fate has been the centre of intense speculation since the US launched a bombing campaign against al-Qaeda and the Taleban Government in Afghanistan at the end of 2001 and then sent ground troops to mop up militants.

You will be killed just as you kill

Voice on audio tape

The failure to capture him despite a massive international manhunt has been a source of continual frustration for the US, which holds the al-Qaeda network responsible for the 11 September 2001 attacks on New York and Washington as well as bombings of Western targets before and after.

The voice said recent attacks such as those in Yemen and Bali were reactions "by the zealous sons of Islam in defence of their religion", citing the continued Israeli-Palestinian conflict.

He warned that America's allies - specifically Britain, France, Italy, Canada, Germany and Australia - would also be targeted if they continued to support Washington.

"Do your governments not know that the White House gangsters are the biggest butchers of this age?" he asked.

He warned: "You will be killed just as you kill."