"I'm not happy about it but then again he's not in violation of the agreement," Trump told reporters on the sidelines of the G7 summit after North Korea's Kim Jong Un supervised the test-firing of a "super-large multiple rocket launcher", state media reported.

Pyongyang fired what appeared to be two short-range ballistic missiles on Saturday, Seoul's military said, the latest in a series of launches in recent weeks in protest at US-South Korean joint military exercises, which wrapped up nearly a week ago.

Trump has staked enormous political capital on personal diplomacy with Kim in a so-far unsuccessful effort to persuade the dictator to give up his nuclear weapons arsenal.

The latest missile tests could further thwart the resumption of the negotiations, which have been stalled since a second summit between Trump and Kim in Hanoi in February collapsed without an agreement.