Japanese will 'watch Sony TV' if US is attacked: Donald Trump

Republican presidential candidate Donald Trump has attacked Japan, one of America's closest allies, saying if the US is attacked, all Japanese would do is "sit home and watch Sony television".

"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.If we're attacked, Japan doesn't have to do anything. They can sit home and watch Sony television. No What kind of deals are these?" Trump asked at an election rally in Des Moines, Iowa.

Japan is a key ally of the United States and its crucial partner in the Asia Pacific region.

Referring to the US-Japan treaty alliance, Trump said that the it is particularly worthy of ridicule.

Japan, Trump said, should be forced to pay 100%of America's military costs for protecting the island nation, not the roughly 50% it pays now.

Currently there are some 47,000 US troops based in Japan.

In his speech, Trump reiterated that the US protects not only Japan but other countries like South Korea, Germany and Saudi Arabia. And these countries don't pay anything near what it costs.

"They have to pay. Because this isn't 40 years ago. It's got to be a two-way street," he asserted.

He also criticised Democratic rival Hillary Clinton policies.

"You know, Hillary Clinton came out and said, 'That's terrible. He's not going to stick with our allies. 'We're going to stick, but once the ally hears her dumb talk, because it's dumb, why would they ever pay?" he asked.