CAIRO, Egypt - Osama bin Laden will release a new video in the coming days ahead of the sixth anniversary of the Sept. 11 attacks in what would be the first new images of the terror mastermind in nearly three years, al-Qaida's media arm announced Thursday.

The White House said any new video from bin Laden would serve to highlight threats the West faces. Analysts noted that al-Qaida tends to mark the Sept. 11 anniversary with a slew of messages, and the Department of Homeland Security said it had no credible information warning of an imminent threat to the United States.

Still, bin Laden's appearance would be significant. The al-Qaida leader has not appeared in new video footage since October 2004, and he has not put out a new audiotape in more than a year, his longest period without a message.

One difference in his appearance was immediately obvious. The announcement had a still photo from the coming video, showing bin Laden addressing the camera, his beard fully black. In his past videos, bin Laden's beard was almost entirely gray with dark streaks.

Bin Laden's beard appears to have been dyed, a popular practice among Arab leaders, said Rita Katz, director of the SITE Institute, a Washington-based group that monitors terror messages.

"I think it works for their (al-Qaida's) benefit that he looks young, he looks healthy," Katz said.

The announcement and photo appeared in a banner advertisement on an Islamic militant Web site where al-Qaida's media arm, Al-Sahab, frequently posts messages.

"Soon, God willing, a videotape from the lion sheik Osama bin Laden, God preserve him," the advertisement read, signed by Al-Sahab. Such announcements are usually put out one to three days before the video is posted on the Web.

IntelCenter, which monitors Islamic Web sites and analyzes terror threats, said the video was expected within the next 72 hours, before the sixth anniversary of the Sept. 11, 2001 suicide hijacker attacks on the World Trade Center and the Pentagon.

The anniversary has always been a major media event for al-Qaida - a chance for it to drum up support among extremists, tout itself as the leading militant group and show off its continued survival.

"They've always gone out of their way to commemorate it," said Ben Venzke, chief executive officer of IntelCenter, which is based in Alexandria, Va. "Historically the anniversary of 9-11 has never been drawn to attacks. It's drawn to video releases."

But the fact that bin Laden is delivering the message is significant, he said. Whether the message will indicate a potential attack will depend on what bin Laden says.

The White House said that any new video message from bin Laden would only underscore the threat the United States and other nations face from extremists.

"Six years after 9/11, the arrests in Germany and Denmark this week and the battles we fight against al-Qaida in Iraq, Afghanistan, southeast Asia and around the world remind us of the continuing threat we face from extremists and why we must continue to take the fight to them wherever they are," said Gordon Johndroe, a spokesman for the National Security Council at the White House.

Homeland Security spokesman Russ Knocke said he could not confirm the existence of a tape, "and there is no credible information at this time warning of an imminent threat to the homeland." But he said increased activity overseas and recent arrests of militants in Germany reinforce the department's assessment that the country is currently in a period of increased risk.

If bin Laden does appear in new footage, it would be the first images of him since an Oct. 29, 2004 videotape, just before the U.S. presidential elections. In that appearance three years ago, he said America could avoid another 9-11 style attack if it stopped threatening Muslims.

The new video would also end the longest period bin Laden has gone without releasing a message. His last audiotape was on July 1, 2006, in which he welcomed new leader of al-Qaida in Iraq succeeding the slain Abu Musab al-Zarqawi.

Bin Laden went silent for a similar long stretch before - from Dec. 28, 2004 to Jan. 19, 2006. That absence sparked widespread speculation he was ill, wounded or possibly dead.

There has been little such speculation since then. U.S. officials have repeatedly said over the past year they believe the al-Qaida leader is alive. He is thought to be hiding in the tribal regions of western Pakistan near the border with Afghanistan.

During bin Laden's silence, his deputy Egyptian-born Ayman al-Zawahri has been frequently issuing videos and audiotapes.

Al-Zawahri appeared in a 2006 video marking the 9-11 anniversary. An anniversary video in 2003 showed footage of bin Laden and al-Zawahri walking through mountain paths, with voice-over messages from both leaders.

- Associated Press writers Eileen Sullivan in Washington and Sarah DiLorenzo in New York contributed to this report.

Osama bin Laden messages

Audio and video messages from Osama bin Laden since Sept. 11, 2001:

- Sept. 6, 2007: Al-Qaida announces Osama bin Laden will release a new video in coming days to mark the anniversary of the Sept. 11, 2001 attacks. A photo of bin Laden in the announcement shows his beard, which in previous videos was mostly gray, was now entirely dark.

- July 1, 2006 - Bin Laden issues a 19-minute audiotape, posted on the Web, endorsing the new leader of al-Qaida in Iraq, Abu Hamza al-Muhajer, and denouncing Iraqi Shiite leaders as traitors.

- June 30, 2006 - Bin Laden issued an audiotape praising al-Muhajer's predecessor, Abu Musab al-Zarqawi, who had been killed in a U.S. airstrike. The message, also 19 minutes, was packaged with an old still photo of bin Laden as well as images of al-Zarqawi taken from a previous video.

- May 23, 2006: Bin Laden purportedly says in an Internet audio tape that Zacarias Moussaoui had nothing to do with the Sept. 11 attacks.

- April 23, 2006: In an audiotape on Arab TV, bin Laden says the West is at war with Islam and calls on his followers to go to Sudan to fight a proposed U.N. force.

- Jan. 19, 2006: Bin Laden warns that his fighters are preparing new attacks in the United States but offers the American people a "long-term truce" without specifying the conditions, in an audiotape broadcast on Al-Jazeera, the pan-Arab satellite channel.

-Dec. 28, 2004: In an hourlong audiotape, he endorses al-Zarqawi as his deputy in Iraq and calls for a boycott of Iraqi elections.

- Dec. 16, 2004: An audiotape posted on an Islamic Web site shows a man identified as bin Laden praising militants who attacked a U.S. consulate in Saudi Arabia earlier that month and calling on militants to stop the flow of oil to the West.

- Oct. 29, 2004: Al-Jazeera airs a video of bin Laden saying the United States can avoid another Sept. 11 attack if it stops threatening the security of Muslims.

- May 6, 2004: In an online audiotape released on Islamic forums, bin Laden offers rewards of gold for the killing of U.S. and U.N. officials in Iraq.

- April 15, 2004: A man identifying himself as bin Laden offers a "truce" to European countries that do not attack Muslims, in an audiotape broadcast on Arab TV stations.

- Jan. 4, 2004: A speaker thought to be bin Laden says on an audiotape broadcast on Al-Jazeera that the U.S.-led war in Iraq is the beginning of the "occupation" of Persian Gulf states for their oil. He calls on Muslims to keep fighting a holy war in the Middle East.

- Sept. 10, 2003: In the first video image of bin Laden in nearly two years, he is shown walking through rocky terrain with top deputy Ayman al-Zawahri. In an accompanying audiotape, a voice purporting to be bin Laden's praises the "great damage to the enemy" on Sept. 11 and mentions five hijackers by name.

- April 7, 2003: In an audiotape obtained by The Associated Press in Pakistan, bin Laden exhorts Muslims to rise up against Kuwait, Saudi Arabia and other governments it claims are "agents of America," and calls for suicide attacks against U.S. and British interests. The CIA determines the 27-minute tape is likely authentic.

- Feb. 13, 2003: An audiotape purported to be of bin Laden reads a poetic last will and testament in a recording first obtained by the British-based Islamic Al-Ansaar news agency. Bin Laden says he wants to die a martyr in a new attack against the U.S.

- Feb. 11, 2003: Bin Laden tells his followers to help Saddam Hussein fight Americans in an audiotape broadcast on Al-Jazeera. U.S. officials say they believe the tape to be authentic.

- Nov. 12, 2002: Al-Jazeera broadcasts a brief audiotape in which a voice attributed to bin Laden threatens new terrorism against the U.S. and its allies, and calls the Bush administration "the biggest serial killers in this age." U.S. experts say the tape can't be authenticated because of its poor quality.

- Dec. 13, 2001: U.S. Defense Department releases videotape of bin Laden in Afghanistan on Nov. 9, 2001, saying the destruction of the Sept. 11 attacks exceeded even his "optimistic" calculations.