Obama: Bin Laden won't be a martyr

Mr Obama's comments, following a meeting with his new team of national security advisers, marked another push by the first-term Illinois senator to battle criticism by presidential rival John McCain and other Republicans that he lacked the national security expertise needed to become president.

Mr McCain has highlighted his own experience as a long-time senator and former prisoner-of-war in Vietnam.

Mr McCain focused his attention on tackling the surging petrol prices that have become a key concern among Americans already worried about the country's economic woes.

The presumptive Republican nominee, who a day earlier had proposed opening US offshore regions to oil and gas exploration - another in his calls for lesser dependence on foreign oil imports.

Meanwhile, Mr Obama told reporters that if Bin Laden were found during his watch, he would bring him to justice in a way that wouldn't allow the terrorist mastermind to become a martyr, but he may be killed if the US government finds him.

"First of all, I think there is an executive order out on Osama bin Laden's head," Mr Obama said at a news conference. "And if I'm president, and we have the opportunity to capture him, we may not be able to capture him alive."

Mr Obama's campaign said he was referring to a classified Memorandum of Notification that President Bill Clinton approved in 1998 - revealed in the 9/11 Commission report - that would allow the CIA to kill Bin Laden if capture were not feasible.

He said he would not discuss what approach he would take to bring Bin Laden to justice. But he said the Nuremberg trials for the prosecution of Nazi leaders are an inspiration because the victors acted to advance universal principles and set a tone for the creation of an international order.

"What would be important would be for us to do it in a way that allows the entire world to understand the murderous acts that he's engaged in and not to make him into a martyr, and to assure that the United States government is abiding by basic conventions that would strengthen our hand in the broader battle against terrorism," Mr Obama said.