Usama bin Laden urged sympathizers to join the "caravan" of martyrs as he praised one of the Sept. 11 suicide hijackers in a new video that emerged Tuesday to mark the sixth anniversary of the attacks on the World Trade Center and Pentagon.

Al Qaeda traditionally issues a video every year on the anniversary, with the last testament of one of the 19 hijackers involved in the Sept. 11, 2001 attacks. This year's video showed hijacker Waleed al-Shehri addressing the camera and warning the U.S.: "We shall come at you from your front and back, your right and left."

The new message, which AP Television News obtained from the IntelCenter monitoring group in suburban Washington, came days after the world got its first current look at bin Laden in nearly three years, with the release of a video Saturday in which the terror leader addressed the American people.

Later in the day it appeared on militant Web sites, with a note from Al Qaeda's media production wing al-Sahab saying it was intentionally sent to television stations before being placed on the Internet.

It begins with an audiotape introduction by bin Laden. While his voice is heard, the video shows a still image of him, raising his finger. In the image, bin Laden has the same dyed-black beard and the same clothes -- a white robe and cap and beige cloak -- that he had in Saturday's video.

But it was not known if the audiotape was recently made. In the past, Al Qaeda has used footage and audio of bin Laden taped long ago for release later.

In the tape, bin Laden praised al-Shehri, saying he "recognized the truth" that Arab rulers were "vassals" of the West and had "abandoned the balance of (Islamic) revelation."

"It is true that this young man was little in years, but the faith in his heart was big," he said.

"So there is a huge difference between the path of the kings, presidents and hypocritical Ulama (Islamic scholars) and the path of these noble young men," like al-Shehri, bin Laden said. "The formers' lot is to spoil and enjoy themselves whereas the latters' lot is to destroy themselves for Allah's Word to be Supreme."

"It remains for us to do our part. So I tell every young man among the youth of Islam: It is your duty to join the caravan (of martyrs) until the sufficiency is complete and the march to aid the High and Omnipotent continues," he said.

At the end of his speech, bin Laden also mentions the Al Qaeda leader in Iraq, Abu Musab al-Zarqawi, who was killed in an U.S. air strike there. Al-Zarqawi followed in the footsteps of al-Shehri and his brothers who "fulfilled their promises to God."

"And now it is our turn," bin Laden says.

After bin Laden speaks, the video of al-Shehri appears. Al-Shehri -- one of the hijackers on American Airlines Flight 11, which hit the World Trade Center -- is seen wearing a white robe and headscarf, with a full black beard, speaking in front of a backdrop with images of the burning World Trade Center.

"We shall come at you from your front and back, your right and left," al-Shehri said, asserting that America would suffer the same fate as the Soviet Union.

He also praised the losses the United States suffered in Somalia in late 1993.

"As for our own fortune, it is not in this world," he said. "And we are not competing with you for this world, because it does not equal in Allah's eyes the wing of a mosquito."

Al-Shehri warned Muslims who strayed to return to their religion and deplored the state of those who abandoned Muslim holy war, or jihad.

"The condition of Islam at the present time makes one cry ... in view of the weakness, humiliation, scorn and enslavement it is suffering because it neglected the obligations of Allah and His orders, and permitted His forbidden things and abandoned jihad in Allah's path," he said.

Suicide attacks for Al Qaeda and other militant groups often videotape last testaments before carrying out their attacks. Every Sept. 11 anniversary, Al Qaeda has used the tapes in a bid to rally its supporters by glorifying its "martyrs."

Bin Laden's new appearances underline the failure to find the terror leader that President Bush vowed in the wake of the Sept. 11 attacks to take "dead or alive."

On Sunday, Bush's homeland security adviser Frances Fragos Townsend sought to play down bin Laden's importance -- and added a taunt, saying he was "virtually impotent."

But terrorism experts say Al Qaeda's core leadership is regrouping in the lawless Pakistan-Afghanistan border region. The latest National Intelligence Estimate says the network is growing in strength, intensifying its efforts to put operatives in the United States and plot new attacks.

Bin Laden's video on Saturday was his first message in over a year -- since a July 1, 2006 audiotape. The images came under close scrutiny from U.S. intelligence agencies, looking for clues to the 50-year-old's health and whereabouts.