A tape purported to be from one of Osama bin Laden's lieutenants has surfaced, and it calls on Muslims to carry out more Sept. 11-style terrorist attacks.

Al-Jazeera television aired excerpts of the 11-minute tape Wednesday.

"Consider your 19 brothers who attacked America in Washington and New York with their planes as an example," says the voice, which Al-Jazeera says is Ayman al-Zawahri, a top bin Laden aide.

"The crusaders and the Jews only understand the language of murder, bloodshed and of the burning towers (World Trade Center attacks) ...Carry arms against your enemies, the Americans the Jews," the voice says.

It goes on to urge attacks against embassies and commercial interests in the U.S., Britain, Australia and, interestingly, Norway. It was not clear why Norway, which did not send troops to the Iraq conflict, is mentioned. The country has been a key mediator between Israelis and Palestinians.

The tape appears to have been made early in the U.S.-led war on Iraq and makes no mention of the recent suicide bombings in Morocco and Saudi Arabia, both blamed on al Qaeda.

U.S. intelligence are trying to determine the authenticity of the tape, which Al-Jazeera's chief editor says was received Tuesday night.

Al-Zawahri, an Egyptian who is regarded as a primary strategist of the al Qaeda terrorists and was with bin Laden in Afghanistan, disappeared soon after Sept. 11, 2001, but is widely thought to have survived U.S. bombing.

On the anniversary of the start of the U.S.-led war in Afghanistan last October, Al-Jazeera released a tape of his alleged voice threatening new attacks against American interests. His last public statement was in a militant newsletter in February.

U.S. intelligence officials have warned in recent days of fresh al Qaeda attacks. On Tuesday, the Department of Homeland Security raised the terror alert level to "high," and the State Department announced the temporary closure of American missions in Saudi Arabia.

The warnings follow two deadly suicide attacks last week -- a triple car bombing that killed 25 people in Riyadh and a series of suicide bombings that killed 28.