Trump 'showing lack of preparedness' on foreign policy, says Obama

Donald Trump's suggestion that the US might not come to the defence of Nato allies is another sign of his "lack of preparedness" on foreign policy, said US President Barack Obama.

In an interview aired on Sunday over Trump's recent comments to the New York Times - in which the presidential nominee suggested that allies who have not paid their Nato dues would not be guaranteed of getting help if Russia invaded - Mr Obama said they were an admission that the US might not live by Nato's "most central tenet."