Is there a country left that he hasn’t ripped on?
At a campaign event in Iowa, Mr Trump also repeated his criticism of countries that do not pull their weight in terms of financial contributions to Nato.
“You know we have a treaty with Japan, where if Japan is attacked, we have to use the full force and might of the United States,” he said.
“If we’re attacked, Japan doesn’t have to do anything. They can sit home and watch Sony television, OK?”
Mr Trump added that the US protects Japan, South Korea, Germany, Saudi Arabia and other nations, and “they don’t pay anything near what it costs”.
“They have to pay. Because this isn’t 40 years ago,” he added.
“It’s got to be a two-way street.”