TOKYO — North Korean weapons tests this month clearly violated United Nations Security Council resolutions, John R. Bolton, the White House national security adviser, said on Saturday, going further than President Trump in characterizing the tests of short-range ballistic missiles.

Mr. Trump initially declared he was “not happy” with the tests but then played down their importance.

“In terms of violating Security Council resolutions, there is no doubt about that,” Mr. Bolton said, speaking in Tokyo in advance of Mr. Trump’s four-day visit to Japan. “I think the prime minister and president are going to talk about making sure the integrity of the Security Council resolutions are maintained,” he said, referring to a Monday summit meeting between Prime Minister Shinzo Abe and Mr. Trump.

Mr. Bolton said that the United States fully supports efforts by Japan’s prime minister to meet with Kim Jong-un of North Korea without any preconditions.