"The survival of Colombia, which is one of the oldest and most stable democracies of Latin America, is now at risk," he said in the videotape broadcast, which was recorded for American television.

"I call on them to refuse any Palestinian referendum because Palestine belongs to the Muslim world," Mr. Zawahiri said in the videotape broadcast Friday on Al Jazeera.

He spoke on a videotape broadcast Wednesday on Al Jazeera's news channel.

A videotape first broadcast Wednesday on the satellite network Al Jazeera showed him surrounded by masked gunmen, pleading for his life and asking the United States government to withdraw troops from Iraq.

Mr. Allawi cited a videotape broadcast Saturday by the network that appeared to show an American being beheaded as an example of the coverage he opposed.

Looking pale and tired, a kidnapped American reporter, Jill Carroll, appeared in a silent videotape broadcast Tuesday by Al Jazeera television.

The videotape broadcast of Dr. Zawahiri was evidently made before reports began to circulate of the Taliban's defeat at Mazar-i-Sharif, an important crossroads in northern Afghanistan.

In a chilling videotape broadcast today, a man identified as one of the Sept. 11 hijackers said his death was intended to send the message that "it is time to kill the Americans in their own homeland."

A group that identified itself as the Islamic Army took credit for the act on a videotape broadcast Monday by Al Jazeera.

Four Western peace advocates abducted in November were shown in a videotape broadcast Saturday, and their captors renewed their threat to kill the hostages if all Iraqi prisoners were not set free.