America says the tape is proof Bin Laden was behind the 11 September attacks

"It is preposterous for anybody to think that this tape is doctored," he said.

"That's just a feeble excuse to provide weak support for an incredibly evil man."

Mr Bush's statements were his first public reaction to the tape, which was released on Thursday and is said by the US to be proof that Bin Laden orchestrated the attacks on New York and Washington, that killed more than 3,000 people.

Many people in the Arab world remain unconvinced.

Mr Bush said that he had mixed emotions over the publication of the tape, fearing that it would add to the suffering of families whose relatives died in the tragedy.

'Compelling evidence'

However he said that releasing the tape was necessary as he knew it to be "a devastating declaration of guilt for this evil person."

Mr Bush also said he was determined to capture Bin Laden dead or alive, and that he was confident that such a capture was possible, regardless of whether it happened in a day or in a year's time.

The video shows Bin Laden joking and laughing with friends and associates about the suicide plane attacks on New York's World Trade Center, in which more than 3,000 people died.

American intelligence officers are said to have recovered the tape from a house in the eastern Afghan town of Jalalabad following the collapse of the ruling Taleban, who were harbouring Bin Laden.

The US says the tape provides compelling evidence that Bin Laden was behind the 11 September attacks.

I was thinking that the fire from the gas in the plane would melt the iron structure of the building and collapse the area where the plane hit and all the floors above it only. This is all that we had hoped for

Osama Bin Laden

Pentagon officials asked four non-government Arabic speakers to listen to the remarks and agree on a uniform translation.

However some in Arab countries mistrust the translation of Bin Laden's remarks, which was necessary as the recording is of both very poor audio and visual quality.

The BBC's Frank Gardner said that opinion in the Arab world was mixed.

In Jordan, political analyst Labib Kamhawi said that even if the video is genuine, Bin Laden's praise for the attacks "does not prove that Bin Laden was responsible" for them.

The defence minister of the ousted Taleban regime in Afghanistan told the BBC that he was doubtful about the recording's authenticity, saying it was unlikely that Bin Laden would have been naive enough to say such things on a recording.

Pakistan's Government, meanwhile, said the broadcast of Bin Laden praising the attacks proved that Islamabad had made "the right decision" in supporting Washington in its military campaign.

Our correspondent adds that the tape is unlikely to win support from many ordinary Arabs because it has been released as Israeli-Palestinian violence increases.