The suspected mastermind of the kidnapping of American reporter Daniel Pearl threatened on Tuesday to make the United States pay dearly if he was extradited from Pakistan to face charges. British-born militant Ahmed Saeed Omar Sheikh, commonly known as Sheikh Omar, had to be gagged by police as he emerged from a Pakistan remand court shouting "Allahu Akbar" and "Down with America." Omar is accused by Pakistani authorities of organizing the kidnapping of Pearl in January while The World Street Journal reporter was researching a story on Islamic militants.