Baghdad, Iraq ? Iraq’s most feared terror leader called on his followers Thursday to show patience and prepare for a long struggle against the Americans, promising in an audiotape posted on the Internet that “ferocious wars … take their time” but victory was assured.

Elsewhere, U.S. troops launched fresh raids around the northern city of Mosul, killing five suspected insurgents, in a bid to rein in guerrillas and safeguard the Jan. 30 national elections. Iraqi forces sealed off main routes into Baghdad a day after a wave of deadly car bombings.

A U.S. Army soldier stands near an Iraqi National Guard truck damaged in an engagement between U.S. forces and insurgents, in which five insurgents were killed. U.S. forces have intensified operations in Mosul to make it safe enough for voters to cast ballots in the country's Jan. 30 elections.

The 90-minute message, purportedly from Abu Musab al-Zarqawi, appeared to be aimed at rallying his forces after the loss of their base in Fallujah and at marshaling support as Iraqis prepare for their first poll since the collapse of Saddam Hussein’s regime.

“Fighters who have taken the path of jihad have to realize the nature and the demands of the battle toward the required goal,” the speaker said. “This group has to be patient in the path that it has taken and … not to hurry victory. The promise of God will be fulfilled no matter what.”

The authenticity of the tape could not immediately be verified. It appeared before President Bush was sworn in for a second term that begins under the shadow of a continuing insurgency in Iraq.