In a BBC interview ahead of this week's state visit to London, Mr Obama described the killing by US Navy Seals of Al Qaeda mastermind Osama Bin Laden in his compound in Abbottabad earlier this month as a 'powerful moment' for America.
The President insisted he wanted to establish a more "co-operative relationship" with the government in Islamabad after the outrage in Pakistan over the US action, which was carried out without notifying the authorities there.
But asked what he would do if the Americans found another "very high value target" in the country - such a top al Qaida figure or the Taliban leader Mullah Omar - he indicated he would act again.
"I've always been clear to the Pakistanis - and I'm not the first administration to say this - that our job is to secure the United States," he told BBC1's The Andrew Marr Show.
"We are very respectful of the sovereignty of Pakistan. But we cannot allow someone who is planning to kill our people or our allies' people - we can't allow those kind of active plans to come to fruition without us taking some action.
"Our hope is, and our expectation is, is that we can achieve that in a way that is fully respectful of Pakistan's sovereignty.
"But I had made no secret - I had said this when I was running for the presidency - that if I had a clear shot at bin Laden that we'd take it." Read More