Al Qaeda leader Osama bin Laden praises martyrdom as a weapon and a path to glory for Muslims in a video claimed to have been intercepted before it appeared on radical Islamist Web sites.
CNN, which noted it could not verify the authenticity of the 40-minute video and had translated it from Arabic into English, said on its website there was no indication of where or when the footage had been shot.
The news channel said the video contained old clips but concluded it had been compiled in the last four weeks. The environment in which bin Laden is shown speaking is similar to that on releases made before the September 11 attacks on the United States by al Qaeda in 2001.
Octavia Nasr, CNN's senior editor for Arab affairs, said bin Laden appears in only a 50-second portion of the video in which he asserts that the Prophet Mohammed had wanted to be a martyr.
"What is this status that the best of mankind wished for himself?" bin Laden asks rhetorically. "He wished to be a martyr. He himself said: 'By Him in whose hands my life is. I would love to attack and be martyred'."
"This glorious prophet who was inspired by God summarized this entire life by these words. He wished upon himself this status. Happy is one who was chosen by God as a martyr," bin Laden said, according to the CNN translation of his remarks.
CNN did not say how the footage had been intercepted. But a segment of the video, produced by al Qaeda's media arm al-Sahab, was seen on the lauramansfield.com website which provides Arabic translations and terrorism analysis.
Bin Laden was wearing army fatigues and appeared to be addressing followers. For the past several weeks, radical Islamist Web sites have proclaimed there will be "good news soon from Sheikh Osama bin Laden," CNN reported.
The US Senate voted on Friday to double the bounty on bin Laden to $50 million and require President George W Bush to refocus on capturing the Saudi-born militant after reports that al Qaeda is gaining strength.
Shortly after the September 11 attacks, Mr Bush said he wanted bin Laden caught dead or alive.
But a year before the US invasion of Iraq in 2003, Mr Bush shifted his emphasis, saying he did not know bin Laden's whereabouts and "I truly am not that concerned about him."
Top US intelligence officials told the House of Representatives Armed Services Committee this week that residents of remote northwestern Pakistan, where bin Laden is believed to be hiding, have proven to be impervious to the financial rewards already offered by the US government.