South Korea's president approved an independent probe yesterday of his successor, Lee Myung-bak, over financial fraud allegations that have cast a cloud over the former Seoul mayor's landslide election win.

The unprecedented investigation into a president-elect emerged from allegations by Lee's liberal rivals that he was directly involved in an investment firm at the center of an alleged stock manipulation case.

Lee has categorically denied the allegations. Prosecutors cleared him earlier this month of wrongdoing while indicting a Korean-American former business partner who was extradited from the US for allegedly spreading false information to boost stock prices and fleeing with millions of dollars in ill-gotten gains.