Amazon has announced 20 finalists in North America for its planned investment of $US5 billion ($7 billion) and 50,000 jobs.

At a speech before the Economic Club of Washington on Thursday, Bezos did not offer any favourites for the project.

Asked about Trump's repeated criticism of both The Washington Post and Amazon, Bezos called it a "mistake" for any elected official to "attack media and journalists".

What Trump "should say [of criticism] is, 'This is right, this is good. I am glad I am being scrutinised,' and that would be so secure and confident," Bezos said.

"But it is really dangerous to demonise the media. It is dangerous to call the media low lifes, it is dangerous to say that they are the enemy of the people.