President Donald Trump tweeted Saturday that he wasn't "disturbed" by recent North Korean missile tests, even though his advisers were.

He said he has "confidence" in North Korean leader Kim Jong Un, and said he "smiled" when he learned Kim had insulted former Vice President Joe Biden.

Top Trump officials like John Bolton, the national security adviser, have condemned the North Korean tests, saying Saturday they violated United Nations resolutions.

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President Donald Trump tweeted Saturday that he has "confidence" in North Korean leader Kim Jong Un and wasn't "disturbed" by the country's missile tests earlier this month that his own advisers have said violated United Nations resolutions.

He also appeared to laugh at Kim's recent insults toward former Vice President and current Democratic presidential candidate Joe Biden, whom he called "an imbecile bereft of elementary quality as a human being" and a "fool of low IQ," according to the North Korean news agency KCNA.

"North Korea fired off some small weapons, which disturbed some of my people, and others, but not me," Trump tweeted. "I have confidence that Chairman Kim will keep his promise to me, & also smiled when he called Swampman Joe Bidan [sic] a low IQ individual, & worse. Perhaps that's sending me a signal?"

Read more: North Korea called Joe Biden a 'fool of low IQ' who is 'seized by ambition for power' after he labeled Kim Jong Un a 'tyrant'

Top Trump administration officials have condemned North Korea's testing of short-range ballistic missiles, and the White House national security adviser, John Bolton, said Saturday that "there is no doubt" the tests violated UN Security Council resolutions.

Bolton said Saturday that the Trump administration has "not heard much" from North Korea since the summit in Hanoi in February, during which Trump refused Kim's request to lift economic sanctions in exchange for dismantling only part of its nuclear weapons system.

Trump spent Saturday in Tokyo, on the first day of a four-day trip where he will hold a summit meeting with Prime Minister Shizo Abe, where the topic of how to handle North Korea is expected to arise.