CAIRO, Egypt — Al-Qaida’s No. 2 figure harshly criticized Libyan leader Moammar Gadhafi in a new audio tape Saturday, accusing him of being an enemy of Islam and threatening a wave of attacks against the North African country because it improved relations with the U.S.

In the 28-minute audio tape called “Unity of the Ranks,” Ayman al-Zawahri also announced that the Libyan Islamic Fighting Group was joining ranks with al-Qaida.

“The Islamic nation is witnessing a blessed step … The brothers are escalating the confrontation against the enemies of Islam: Gadhafi and his masters, the Washington crusaders,” al- Zawahri said. The recording could not be independently verified, but it appeared on a Web site commonly used by insurgents.

The recording also carried a message from Abu Laith al-Libi, a Libyan al-Qaida commander in Afghanistan who accused Gadhafi of decades of tyranny.

“He is the tyranny of Libya and is dragging the country to the swamp,” al-Libi said in the recording that also featured old video footage of him walking with other masked gunmen.

“After long years, he (Gadhafi) discovered suddenly that America is not an enemy … and is turning Libya into another crusader base,” said al-Libi, who has appeared in several recent al-Qaida videos.

For decades, the U.S. had regarded Libya as a pariah state after Gadhafi came to power in a military coup in 1969 and turned against the West.

Libya was demonized for sponsoring terrorist groups and for trying to undermine pro-Western governments in Africa. Washington put Libya on a list of state sponsors of terrorism and imposed sanctions that barred American companies from doing business in the oil-rich country. In 1986, U.S. warplanes carried out airstrikes against Libya.

But the tide started to turn in 2003, after Gadhafi’s surprise decision to dismantle Libya’s nuclear program. That same year, Libya reached a $2.7 billion settlement with families of the victims of the 1988 Pan Am bombing over Lockerbie, Scotland, and the next year it paid $170 million in compensation to the families of the 170 victims of the 1989 bombing of a French UTA passenger jet.

The U.S. resumed full diplomatic relations with Libya last year and removed Libya from the State Department’s list of terrorism sponsors.

The State Department also has praised Libya’s cooperation in helping the U.S. in the search for al-Qaida and other terror suspects in the Middle East and North Africa.