In an interview for CBS's "Face the Nation," Trump downplayed the significance of North Korea's "small missile launch," which occurred early Saturday. But when asked by host John Dickerson if he would consider military action in response to another nuclear test, Trump responded: "I don't know. I mean, we'll see."
Still, Trump expressed tepid admiration for North Korea's leader.
"People are saying, 'Is he sane?' I have no idea," the President said, before noting Kim Jong Un's rise to power at a young age.
"So obviously, he's a pretty smart cookie," he said. "But we have a situation that we just cannot let -- we cannot let what's been going on for a long period of years continue."
Later, when asked at during a factory tour before a rally in Harrisburg, Pennsylvania, to mark his 100th day in office what his message on North Korea is, Trump told reporters: "You'll soon find out, won't you?"
Pressed on whether that meant military action, Trump said, "You'll soon find out."
The missile launched Saturday blew up over land in North Korean territory,
said US Navy Cmdr. Dave Benham, a spokesman for the US Pacific Command.
Trump cast the launch as a direct snub of China, one of North Korea's only allies and a nation seen by the Trump administration as a potential US ally in efforts to stamp out Pyongyang's nuclear program.
"North Korea disrespected the wishes of China & its highly respected President when it launched, though unsuccessfully, a missile today. Bad!" Trump tweeted after the launch.
Pyongyang's show of defiance, at a time when its military ambition has reached its highest level in years, came just hours after Secretary of State Rex Tillerson addressed a special meeting at the United Nations and called for increased pressure on North Korea.
"All options for responding to future provocations must remain on the table," Tillerson said
. "Diplomatic and financial leverage or power will be backed up by willingness to counteract North Korean aggression with military action, if necessary."
The launch was swiftly condemned by South Korean and Japanese leaders. South Korea's foreign ministry called it a "provocative action," saying it clearly violated UN Security Council resolutions and constituted a serious threat to peace and security.
North Korea has filed a number of missiles this year, with mixed success
. The most recent two -- fired on April 16 and April 29 -- both failed.
Each launch, however, gives North Korea information about way to improve, though the primary concern is if and when it will conduct a sixth nuclear test.
North Korea is believed to be refining the technology to mount a nuclear warhead on an intercontinental missile which could potentially reach US targets.
"As long as America continues its hostile acts of aggression, we will never stop nuclear and missile tests," said Sok Chol Won, director of North Korea's Institute of Human Rights at the Academy of Social Sciences.
North Korea on Saturday said it is developing nuclear weapons for self-defense and as a deterrent to the United States, according to an unofficial translation of a statement released by an official in Pyongyang's mission to the UN.
The statement, which came in response to CNN's questions about the latest launch, did not acknowledge Saturday's missile test.
North Korea has urged an end to joint US-South Korea military exercises, which China also says should be halted in exchange for Pyongyang dismantling its weapons program.
The US says that's not going to happen, citing the need to be prepared.