A new tape purporting to come from Osama bin Laden has called on Iraqis to carry out suicide attacks against "enemies of Islam" and to protect themselves in trenches against US bombardment.
US officials believe the voice on the tape, broadcast last night on the Al-Jazeera Arab satellite station, is that of the al-Qaeda leader.
The tape was given to Al-Jazeera but acquired by Washington a day before it was aired. The White House would not reveal last night how it had been obtained in advance by American intelligence.
"With all the might of the enemy, they were unable to defeat us" in Afghanistan, the speaker says, referring to his escape from US aerial bombardment at Tora Bora. "We hope that our brothers in Iraq will do the same as we did."
In the 16-minute tape he distanced himself from the secular regime of President Saddam Hussein, but gave advice to Iraqis on how to fight the Americans.
"We are following with great concern the preparations of the crusaders to launch war on the former capital of Muslims and to install a puppet government," he said.
The coming US attack on Iraq was designed "to achieve the Zionist dream" of establishing a greater Israel.
"Fight these despots," he urged. "I remind you that victory comes only from God. . .
"We stress the importance of suicide bombings against the enemy, these attacks that have scared Americans and Israelis like never before."
He advised the Iraqis to draw the Americans into combat in the cities "because they will have big casualties." "Don't worry about the American lies and their smart bombs and laser ones.
"They look for only the clear obvious targets. The most effective means to devoid the aerial force of its content is by digging large numbers of trenches and camouflage them."
Anyone who helped the United States "from the Iraqi hypocrites or Arab rulers . . . whoever fights with them or offers them bases or administrative assistance, or any kind of support or help, even if only with words, to kill Muslims in Iraq, should know that he is an apostate . . . and bloodshed is permissible"
He added "Do not trust Jews and Christians as friends as they are only friends to each other."
Mr Yasser Thabet, a broadcast editor at Al-Jazeera, said the tape appeared to be authentic as it was acquired through the same means as previous bin Laden statements.
The existence of the new recording was first revealed by the US Secretary of State, Mr Colin Powell, at a congressional hearing yesterday morning, eight hours before it was played on Al-Jazeera.
Mr Powell inadvertently "scooped" Al-Jazeera, officials said, as he had received the transcript on Monday evening and mentioned it in Congress in the belief that it was being broadcast at that time.
However, by announcing its existence first Mr Powell was able to depict Iraq as allied with terrorism, a link he made in his UN presentation last week. Baghdad has denied co-operating with al-Qaeda.
Bin Laden once again "speaks to the people of Iraq and talks about their struggle and how he is in partnership with Iraq," Mr Powell said.
"This nexus between terrorists and states that are developing weapons of mass destruction can no longer be looked away from and ignored."
The tape has emerged at a time when the US has upgraded the national terrorist threat level from "elevated" to "high".
The al-Qaeda terrorist network remains a "resourceful, merciless" foe dedicated to committing more attacks, the head of the FBI, Mr Robert Mueller, told a separate Congress hearing.
The tape is an embarrassing reminder to the White House that the main target of the US war on terrorism is still at large.
The last Bin Laden tape was broadcast on Al-Jazeera on November 12th.
In a joint appearance before the Senate Intelligence Committee, Mr Mueller and CIA Director, Mr George Tenet, warned of plots to use chemical, biological and radiological weapons against lightly guarded places such as shopping malls or universities.
New York police have warned of threats to the subway system, and extra police have been drafted in to protect tunnels and bridges.
Mr Tenet said intelligence pointed to attacks that could occur this week, coinciding with the Muslim hajj holy days, possibly using a "dirty bomb" that spews out radiological material.
"The intelligence is not idle chatter on the part of terrorists and their associates," he said.
"It is the most specific we have seen, and it is consistent with both our knowledge of al-Qaeda doctrine and our knowledge of plots this network - and, particularly, its senior leadership - has been working on for years."