Thousands of people were evacuated Wednesday from the world's tallest buildings, the Petronas Twin Towers, and from the IBM building in Malaysia after bomb threats were phoned in.The threat against the 88-story Petronas towers came 12 hours after hijackers flew jetliners into the World Trade Center in New York and into the Pentagon in Washington.Bomb squads found no explosives in the Petronas towers, and workers and shoppers were allowed to return three hours later, around noon. No one was hurt, but six people fainted during the evacuation.Just as the Petronas towers were declared safe, another bomb threat was phoned in to the IBM building in Kuala Lumpur. Some 2,000 people were evacuated as police combed the 24-story building, which houses IBM Malaysia, Standard Chartered Bank and other firms. No bomb was found.The Petronas Twin Towers opened in 1996 and soar 1,483 feet and symbolize Prime Minister Mahathir Mohamad's ambition to turn his Southeast Asian nation of 23 million people into a fully developed country.The towers surpasses Chicago's Sears Tower as the world's tallest building. The World Trade Center towers in New York were the third tallest. The Petronas towers featured in the film "Entrapment" with Sean Connery and Catherine Zeta-Jones.