He has vowed to stop the North from being able to hit the US with a nuclear missile and Vice-President Mike Pence last week stressed that the "era of strategic patience" was over.
Though it has warned "all options are on the table", the Trump Administration said yesterday it aimed to push North Korea into dismantling its weapons programmes through tougher sanctions and diplomatic pressure, and it remained open to talks.
Secretary of State Rex Tillerson, Defence Secretary Jim Mattis and Director of National Intelligence Dan Coats described North Korea as "an urgent national security threat and top foreign policy priority".
The US signal of a willingness to exhaust non-military avenues came as the USS Carl Vinson aircraft carrier group approached Korean waters, where it will join the USS Michigan nuclear submarine.
North Korea, which on Wednesday conducted its biggest ever artillery exercise to mark the 85th anniversary of its military's creation, says it needs to develop weapons to defend itself from US aggression.
A North Korean official speaking on CNN said the country would not be influenced by outside events.
"As long as America continues its hostile acts of aggression, we will never stop nuclear and missile tests," said Sok Chol Won, director of the North's Institute of Human Rights at the Academy of Social Sciences.
North Korea's official Rodong Sinmun newspaper said it was "entirely because of the US" that global denuclearisation had not been achieved.
"So US officials should know this clearly and feel responsible, not play with their beaks thoughtlessly," it said.
South Korea has moved parts of a US Terminal High Altitude Area Defence, or Thaad, missile defence system to its deployment site, on what had been a golf course, about 250km south of the capital, Seoul, signalling a faster installation of the system.
Several hundred South Korean villagers protested near the site, hurling water bottles at vehicles moving the parts in.
The top US Commander in the Pacific, Admiral Harry Harris, said that the Thaad system would be operational "in coming days" bolstering the ability to defend the US ally and the 28,500 US troops stationed there.
South Korea's Defence Ministry, asked if the Thaad unit would be undergoing trials, said the deployment had progressed further than it and the US had earlier indicated.
"No, not a trial operation. The capability that's been deployed by the United States and South Korea now means that if North Korea provokes, it is a capability that can respond," ministry spokesman Moon Sang Gyun told a briefing.
A photograph taken of the site showed a Thaad interceptor on the back of a mobile launcher erected and pointed skywards on green lawn as a military helicopter hovered nearby.
The US and South Korea agreed last year to deploy Thaad to counter the North Korean threat.
But China says the system's advanced radar can penetrate deep into its territory and undermine its security and is adamant in its opposition. The influential Chinese tabloid, the Global Times, run by the Communist Party's official People's Daily, denounced Thaad, saying it undermined China's effort to ease tension on the peninsula.
"South Korea must pay the price for its arrogance," it said.
"Seoul, by turning the peninsula into a powder keg together with the North, is playing with fire."
The frontrunner in South Korea's May 9 presidential election has called for a delay in Thaad deployment, saying the new Seoul Administration should make a decision after gathering public opinion and more talks with Washington.
Moon Jae In, who is leading in opinion polls, said yesterday that if North Korea does conduct another nuclear test, "dialogue between the two Koreas will be practically impossible for a very long time, and considering the single five-year presidency, it will be difficult to improve ties".
