'President Clinton had opportunities to get Osama bin Laden. President Bush had opportunities to get Osama bin Laden. I know how to do it and I'll do it,' he told ABC's World News in an interview.

'I understand and I have the knowledge and the background and the experience to make the right judgments. Senator Obama does not,' Mr McCain said in a reference to his Democratic rival for the White House, Barack Obama.

Mr McCain, who was a Navy fighter pilot and spent five years as a prisoner of war in Vietnam, said Mr Obama 'doesn't know how - how the world works nor how the military works.'

An early backer of the Iraq war, the Arizona senator has assailed Mr Obama's judgment in opposing the war.

He was asked to respond to Mr Obama's accusation last week that Mr McCain's focus on the Iraq war rather than pursuing Al-Qaeda had allowed Osama to escape in Afghanistan.

Al-Qaeda is blamed for the Sept 11, 2001, attacks on the United States which killed almost 3,000 people in New York, Washington and Pennsylvania. --REUTERS