US President Donald Trump on Friday described his telephone talks with Chinese counterpart Xi Jinping were "very warm," while he reassured Japan that improved US-Chinese ties were not a threat to Tokyo.

"We had a very, very good talk last night, and discussed a lot of subjects. It was a long talk," Trump told a joint press conference with Japanese Prime Minister Shinzo Abe.

He said he and Xi were "in the process of getting along very well, and I think it will be very much of a benefit to Japan."