NATO cannot be an 'a la carte' military alliance dependent on the whims of the U.S. president, the European Union's foreign policy chief Josep Borrell said on Monday, as he responded to comments made by Donald Trump regarding NATO over the weekend, Paralel.Az reports.

Former U.S president Trump had suggested the United States might not protect NATO allies which don't spend enough on their own defence from a potential Russian invasion.

Asked to respond to Trump's comments, Borrell said: "Let me be sarcastic. During this campaign, we will see and listen to many things. Let’s be serious. NATO cannot be an “à la carte” military alliance. NATO cannot be an alliance that works depending on the ”humeur” of the President of the United States in those days. It is not “Now yes. Tomorrow, no. It depends, who are you?”. No, come on, let’s be serious. NATO cannot be an alliance “à la carte”. It exists, or it does not exist. But I am not going to spend my time commenting on any silly idea that comes during this electoral campaign in the United States."