An al Qaeda leader has accused Saudi Arabia in an Internet video of giving in to Islam's Western enemies by calling for moderation and a dialogue with Jews and Christians.

The message from Abu Yahya al-Libi came as Saudi Arabia was reported to be planning a conference of senior world Muslim clerics this year to promote moderation and fight extremism, after King Abdullah called in March for an inter-faith dialogue.

"He who is called the defender of monotheism by sycophantic clerics is raising the flag of brotherhood between religions...and thinks he has found the wisdom to stop wars and prevent the causes of enmity between religions and peoples," Libi said, in a clear reference to King Abdullah.

"By God, if you don't resist heroically against this wanton tyrant...the day will come when church bells will ring in the heart of the Arabian Peninsula. And the case of Qatar is not far away from you," Libi said.

He was referring to Qatar's decision in March to allow the opening of the first church in the US-allied Gulf Arab state.

Neighbouring Saudi Arabia, which follows a strict school of Islam, still bans followers of other faiths from building public houses of worship in the birthplace of Islam.

The video was posted on Thursday on Islamist websites often used by al Qaeda and its supporters.

"The tool (of proponents of moderation) is subjugation. Their substance is to please and appease the West, even if this destroys Allah's religion," said Libi, who is believed to have escaped from a US jail in Afghanistan in 2005.

"There is no moderation, no rapprochement, and no collaboration between us and infidel peoples. Where do light and darkness ever meet?" said the bearded Libyan, who has also issued previous statements on theological issues.

"Let them (proponents of moderation) know that Islam is the religion of the sword," he added as he stood inside what appeared to be a mud house.

King Abdullah has led the Saudi Government's attempt to wipe out al Qaeda militants who launched a violent campaign against the US-allied royal family in 2003.

The king is regarded as a reformer, although diplomats say clerics and their allies have resisted his plans for change.