Donald Trump admits criticising NATO while 'not knowing much' about it

United States President Donald Trump has admitted his 2016 comment that the North Atlantic Treaty Organisation (NATO) was "obsolete" was made when he was "not knowing much about NATO".

In a new interview with the Associated Press (AP), the President said he was caught off guard when asked about NATO by CNN's Wolf Blitzer during the presidential campaign last year.

He said the reason he didn't know much was because he was not yet in government.

"People don't go around asking about NATO if I'm building a building in Manhattan," Mr Trump said to AP.

"Wolf ... asked me about NATO and I said two things. NATO's obsolete - not knowing much about NATO, now I know a lot about NATO - NATO is obsolete, and I said, 'And the reason it's obsolete is because of the fact they don't focus on terrorism.' You know, back when they did NATO there was no such thing as terrorism."

Earlier in April Mr Trump backtracked on his comment that NATO was obsolete, but added that member nations must pay their share to be part of it.