Militants urged to attack oil targets

In a video interview posted on a website used by Islamic extremists, Zawahri said that oil had been stolen from the Muslims by "the thieves who rule our countries".

The message emerged as Saudi Arabia's King Abdullah appealed to the Organisation of the Islamic Conference - the world's biggest Muslim body - in the holy city of Mecca to unite and tackle extremists who he said had hijacked their religion.

"It bleeds the heart of a believer to see how this glorious civilisation has fallen from the height of glory to the ravine of frailty, and how its thoughts were hijacked by devilish and criminal gangs that spread havoc on earth," the king said.

The last public statement from bin Laden himself was in an audiotape issued in December 2004, when he urged Muslims to wage holy war against US forces and the government in Iraq.

There have been rumours that bin Laden was killed or wounded in the October earthquake in Pakistani-controlled Kashmir, which claimed the lives of 79,000 people.

In the internet video, Zawahri said: "I bring a message of joy to all Muslims and mujahideen that al-Qaeda is spreading, expanding and strengthening.

"Its prince, Sheikh Osama bin Laden, is still leading its jihad [holy war]."

He said a new front in al-Qaeda's campaign should be opened. "I call on mujahideen to concentrate their attacks on Muslims' stolen oil, most of the revenues of which go to the enemies of Islam while most of what they leave is seized by the thieves who rule our countries," Zawahri said.

Zawahri's remarks were said by his off-camera interviewer to have been recorded to mark the fourth anniversary of the 9-11 attacks on the United States, but were only released yesterday, apparently to contradict claims that bin Laden was dead.

The Arabic network, al-Jazeera, said it had aired excerpts from the same interview on 19 September, but not the comments about attacking oil installations or that bin Laden was still actively in charge of al-Qaeda.

In Washington, a US official said intelligence analysts were examining the tape, but declined all other comment.

King Abdullah, one of the objects of Zawahri's wrath, said the world's billion Muslims were weak and divided and should come together to tackle the threat posed by al-Qaeda and other extremist groups.

Saudi Arabia was home to 15 of the 19 al-Qaeda hijackers who killed 3,000 people in the United States in the attacks of 11 September, 2001. US critics have blamed the kingdom's strict Wahhabi school of Islam for fostering extremism. The king called for greater efforts to promote tolerance. "I look forward to the spread of a moderation that embodies the tolerance of Islam," he said.

The king was speaking at the start of a two-day summit in Mecca of the 57-member OIC, convened to address what he said were grave dangers facing the Muslim nation.

"We don't have the luxury of blaming others for our own problems," said Ekmelettin Ihsanoglu, the OIC's secretary-general, portraying the Muslim world confronting one of "the most critical eras of its history".

"Helplessness, dispossession, marginalisation, all of these lead to the growth and spread of extremist ideas," he said.

Abdullah Ahmad Badawi, the Malaysian prime minister, also issued a solemn warning, saying that Muslims across the world were in a state of "disunity and discord" worse than at any time in 14 centuries of Islamic history.

"Thousands of our brothers and sisters in Iraq, Afghanistan, Syria, Iran and Sudan and similar places, are living in fear of war and violence," he said. "Many more are living under threats of poverty and backwardness."

The Mecca gathering has endorsed a ten-year plan for Muslim countries that involves better education, faster economic development, more trade, religious moderation and more rights for women.