The suspected planner of the September 11 attacks has been handed over to the US following his arrest in Pakistan on Saturday. Khalid Sheikh Mohammed, who has been on the run for a decade, was turned over to US custody and taken to an undisclosed location outside the country within hours of his capture, Pakistani officials say. Washington has described him as one of al Qaeda leader Osama bin Laden's "most senior and significant lieutenants". His capture prompted joy in the US government. "That's fantastic!" was President George W Bush's reported reaction to the news. The 37-year-old Kuwaiti was arrested with two other men in a joint Pakistani-CIA operation in a pre-dawn raid in Rawalpindi, near the capital Islamabad.