U.S Republican presidential candidate Sen. John McCain acknowledges supporters at an airport in Minneapolis, Minnesota, where he arived to attend the 2008 Republican National Convention September 3, 2008. McCain said on Wednesday that if elected president, he will capture al Qaeda leader Osama bin Laden. REUTERS/Brian Snyder

ST. PAUL (Reuters) - Republican candidate John McCain said on Wednesday that if elected president, he will capture al Qaeda leader Osama bin Laden.

“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,” McCain said in a reference to his Democratic rival for the White House, Barack Obama.

McCain, who was a Navy fighter pilot and spent five years as a prisoner of war in Vietnam, said 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 Obama’s judgment in opposing the war. He was asked to respond to Obama’s accusation last week that McCain’s focus on the Iraq war rather than pursuing al Qaeda had allowed bin Laden 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.