President Donald Trump on Friday said North Korea's leader would "regret" making any "overt" threat, keeping up the pressure after a string of combative warnings.
"If [King Jong Un] utters one threat in a form of an overt threat — which, by the way, he has been uttering for years, and his family has been uttering for years — or if he does anything with respect to Guam or any place else that's an American territory or an American ally, he will truly regret it. And he will regret it fast," Trump told reporters ahead of a workforce development meeting at his New Jersey golf club.
Trump's latest warning came hours after he issued his bluntest statement yet to North Korea, saying the U.S. military is "locked and loaded" to respond to a Pyongyang provocation.
In a tweet, Trump said, "Military solutions are now fully in place, locked and loaded, should North Korea act unwisely. Hopefully Kim Jong Un will find another path!"
It is not clear what exactly the U.S. military has done to get its responses "fully in place." Asked Friday about what he meant by the tweet, Trump said it is "very, very easy to understand," adding, "what I said is what I mean."
Trump on Friday also shared a U.S. Pacific Command tweet from Thursday saying U.S. B-1B bombers on Guam "stand ready" to fulfill a "fight tonight" mission "if called upon to do so."
On Tuesday, The Washington Post, citing a confidential U.S. intelligence assessment, reported that North Korea had successfully produced a miniaturized nuclear warhead that could fit inside its missiles.
The U.S. has repeatedly stressed that it wants dialogue and economic sanctions to deter Pyongyang from pursuing its nuclear and missile programs. So far, North Korea has continued tests in the face of sanctions. The latest attempt to punish the nation economically came Saturday, when the U.N. Security Council approved a sanctions resolution. China and Russia voted for the measure.
The conflict escalated after a subsequent warning from Trump, using language similar to the North's own frequent saber rattling: If it were to make any more threats against the U.S., the president said, Pyongyang "will be met with fire, fury, and frankly, power, the likes of which this world has never seen before."
Trump then strengthened his rhetoric again on Thursday, saying "maybe that statement wasn't tough enough." He did not comment on whether the U.S. is considering a pre-emptive strike on North Korea.
Trump's latest warning comes as China's state-run newspaper said Beijing should remain neutral if North Korea launches an attack that threatens the United States. Pyongyang has threatened to fire missiles near the U.S. Pacific territory of Guam.
"China should also make clear that if North Korea launches missiles that threaten U.S. soil first and the U.S. retaliates, China will stay neutral," the Global Times, which is widely read but does not represent official government policy, said in an editorial.
"If the U.S. and South Korea carry out strikes and try to overthrow the North Korean regime and change the political pattern of the Korean Peninsula, China will prevent them from doing so," it said.
Later Friday, the president took a more measured tone on North Korea after meeting with Secretary of State Rex Tillerson, U.N. Ambassador Nikki Haley and H.R. McMaster, national security advisor. Trump said that the U.S. is working "very closely" with China and other countries in dealing with Pyongyang.
Trump also said he has a phone call scheduled with Chinese President Xi Jinping on Friday evening.
Trump has attempted to leverage China, North Korea's only major ally, to apply more economic pressure on the isolated regime. On Thursday, he said Beijing "can" and "will" do a lot more to keep North Korea in check.
He also warned on Thursday that, "if [Kim Jong Un] does something in Guam, it will be an event the likes of which nobody's seen before, what will happen in North Korea."
— CNBC's Leslie Shaffer and Reuters contributed to this report.