By Frank Gardner BBC security correspondent

An internet audio clip reported to be that of an al-Qaeda spokesman has claimed that Osama Bin Laden and other leaders are safe and planning their next attacks.

The Arabic-language Middle East Broadcasting Company broadcast a message on Tuesday night which warned of guerrilla warfare and assassinations.

It is the second such message apparently coming from al-Qaeda in 24 hours, speaking of a new phase in the group's war against America.

Al-Qaeda has used media statements to spread its message

Talking in Arabic, the man said that the Taleban leader, Mullah Omar was well and that the Taleban was reorganising.

He said that the fighters, who he called holy warriors, were preparing for guerrilla warfare.

Cryptically, he added that al-Qaeda had succeeded in penetrating its enemies bases, which he said were weak.

Al-Qaeda 'intact'

On Tuesday, the Algerian newspaper Al Youm published an interview it said was with al-Qaeda's chief spokesman Sulaiman Abu Ghaith.

He gave an interview via e-mail in which he heaped scorn on America and vowed to attack US and Jewish targets.

He said that the US campaign had failed and that al-Qaeda was intact and functioning smoothly.

The Kuwaiti-born Islamic extremist was seen in videos last year sitting with Osama Bin Laden, and he aired his threats to the West on the internet last month.

In this latest interview, Mr Abu Ghaith is quoted as declaring that al-Qaeda's military, intelligence, and economic infrastructures had not been affected by Washington's war on terrorism.

The newspaper quotes him as saying that al-Qaeda was even more determined to continue its work and, as he put it, "to avenge the blood of innocent people".

The interviewee went on to say that al-Qaeda would not stop attacking America as long as the US persisted in what he called "its unjust policy against Muslims and in favour of Jews and Christians".

Morale weakening?

If the interview was indeed with the al-Qaeda spokesman, then there was nothing radically new in it.

Last month, a Saudi cleric criticised Sulaiman Abu Ghaith for issuing what he called "empty threats", a practice which he said was un-Islamic.

Over the last few months, al-Qaeda has made several threats to attack the West. But so far the attacks blamed on its followers have been minor compared to those launched on 11 September.

Some intelligence analysts believe that the messages show that after the defeat of the Taleban, al-Qaeda is having problems maintaining morale amongst its followers.