A new recording from al-Qaeda leader Osama Bin Laden has been posted on an Islamist website.
The recording is Bin Laden's fourth message this year
He praised Abu Musab al-Zarqawi, the leader of al-Qaeda in Iraq killed three weeks ago, as a "lion of holy war".
The video, lasting 19 minutes, shows a still picture of Bin Laden, and moving pictures of al-Zarqawi.
Unnamed US officials said the recording was authentic. It is the fourth audio message Bin Laden has released since the start of this year.
However, no new video images of the al-Qaeda leader have appeared since October 2004.
Last week a video was broadcast purportedly showing the deputy leader of al-Qaeda, Ayman al-Zawahri, in which he paid tribute to Zarqawi and said his death would be avenged.
In the latest recording, Bin Laden addresses US President George W Bush, warning him not to be "too happy" about Zarqawi's death, "for the banner [of al-Qaeda in Iraq] hasn't dropped but has passed from one lion of Islam to another lion".
Bin Laden says al-Qaeda will go on with operations against the US and its allies.
"We will continue, God willing, to fight you and your allies everywhere," he said, "in Iraq and Afghanistan and in Somalia and Sudan until we waste all your money and kill your men."
In an apparent reference to a campaign against Iraq's Shias by Zarqawi, Bin Laden addressed "those who accuse Abu Musab of killing certain sectors of the Iraqi people".
"Abu Musab had clear instructions to focus his fight on the occupiers," he went on, "particularly the Americans and to leave aside anyone who remains neutral."
He called on President Bush to return Zarqawi's body to his family, and used rhyming couplets to eulogise the dead al-Qaeda leader.