Washington: President Donald Trump has downplayed the significance of recent missile testing by North Korea and vouched for the nation's dictator, Kim Jong Un, calling him a "friend" who has a "great and beautiful vision for his country."

In morning tweets, Trump acknowledged that the short-range ballistic missile tests violate United Nations sanctions on North Korea but said the testing did not violate the agreement signed by the two leaders last year at their Singapore summit, which focused on nuclear weapons.

Kim Jong-un and Donald Trump met in the demilitarised zone earlier this year. Credit:AP

"Chairman Kim does not want to disappoint me with a violation of trust, there is far too much for North Korea to gain - the potential as a Country, under Kim Jong Un's leadership, is unlimited," Trump wrote.

"Also, there is far too much to lose," Trump continued. "I may be wrong, but I believe that Chariman (sic) Kim has a great and beautiful vision for his country, and only the United States, with me as President, can make that vision come true. He will do the right thing because he is far too smart not to, and he does not want to disappoint his friend, President Trump!"