Al-Qaeda's Number 2 Ayman al-Zawahri urged Muslims to intensify their resistance against the US and warned of new terror strikes in a video aired by CNN early Monday on the fifth anniversary of the Sept 11 attacks.
It was the latest in a flurry of Al-Qaeda videos released ahead of the anniversary.
"You gave us every legitimacy and every opportunity to continue fighting you," al-Zawahri said, addressing the US in the video aired by CNN, which appeared to be new.
"You should worry about your presence in the (Persian) Gulf, and the second place you should worry about is Israel."
The bespectacled Al-Zawahri was dressed in white and seated in front of a wall of bookshelves.
"Your leaders are hiding from you the true extent of the disaster," he said.
"And the days are pregnant and giving birth to new events, with Allah's permission and guidance."
The video appeared to be new. In it, al-Zawahri refers to Israel's bombardment of Lebanon this summer and the capture of Israeli soldiers by Hezbollah and Palestinian militants in Gaza.
Egyptian-born Al-Zawahri, Osama bin Laden's deputy, criticised the West for supplying Israel with weapons and called on the Muslim world "to rush with everything at its disposal to the aid of its Muslim brothers in Lebanon and Gaza."
The video could not be located by the agency on any militant websites that normally carry messages and videos from al-Zawahri and other Al-Qaeda figures.
As-Sahab, the terror network's media arm, posted notices late Sunday that the video would be posted shortly but it was not yet available early on Monday.
It was unclear where CNN got the video. The network quoted a counter-terrorism expert as saying the video had appeared on the website for As-Sahab, but the production company normally uses other Islamic websites to post its material.
The SITE Institute, an organisation that monitors militant websites, later said it too had obtained a copy of the one-hour, 16-minute video.
Late on Sunday, another videotape posted on the Internet, purportedly by Al-Qaeda, showed previously unseen footage of a smiling bin Laden and other commanders in a mountain camp apparently planning the September 11 attacks on New York and Washington.
That tape's documentary-like retrospective of the five years since the attacks was unusually long -- 91 minutes, split into two segments -- and sophisticated in its production quality compared to previous Al-Qaeda videos.
The footage -- with English subtitles -- surfaced on the eve of the fifth anniversary of the attacks, on a website that frequently airs messages from bin Laden's terror network.
"Planning for September 11 did not take place behind computer monitors or radar screens, nor inside military command and control centres, but was surrounded with divine protection in an atmosphere brimming with brotherliness ... and love for sacrificing life," an unidentified narrator said.
The video released Sunday, stamped with the emblem of As-Sahab, Al-Qaeda's media branch, was titled "Knowledge is For Acting Upon" and subtitled "The Manhattan Raid."