NEW YORK US President Barack Obama has expressed confidence that Pakistan's nuclear weapons are safe and said that the Pakistani military is equipped to prevent extremists from taking over the nuclear arsenal.

In an interview with Newsweek published on Sunday, the president stressed that 'Pakistan's sovereignty has to be respected' and said he felt strongly that Pakistani military was up to the task.

He was asked if he would be willing 'to keep the option alive to have American troops secure those nuclear weapons if the country gets less stable'?

President Obama said there was 'decided shift' in Pakistan army's recognition that 'the threat from extremism is a much more immediate and serious one than the threat from India'.

'We are trying to strengthen them as a partner, and one of the encouraging things is, over the last several weeks we've seen a decided shift in the Pakistan army,' he said.