Trump has said he spoke with Chinese President Xi Jinping about Pyongyang's "provocative actions", and he vowed that additional major sanctions will be imposed on North Korea.
Last week, North Korea shattered 2½ months of relative quiet by firing off an intercontinental ballistic missile that some observers say showed the reclusive country's ability to strike the U.S. East Coast.
The US and South Korea will launch a major air force exercise involving hundreds of aircraft on Monday, a move denounced by North Korea for bringing the region to the "brink of nuclear war".
A parliamentary committee on defense on Saturday approved a resolution to condemn North Korea's latest long-range missile test and its violation of an armistice agreement that ended the 1950-53 Korean War.
The comments came as White House National Security Adviser HR McMaster warned of the "increasing" possibility of war with the impoverished but nuclear-armed North. North Korea released dozens of photos and a video after Wednesday's launch of the new Hwasong-15 missile, which North Korean leader Kim Jong Un declared had "finally realized the great historic cause of completing the state nuclear force".
With every missile launch or nuclear test, Kim has improved his country's capabilities, McMaster said.
A South Korean defense official confirmed to CNN on Sunday that the United States is sending dozens of high-end fighters, bombers and support aircraft to the drills.
The missile is said to have flown almost 2,800 miles high and for a distance of more than 600 miles.
Cloaked with the world's most advanced stealth coating, the F-22s and F-35s would likely be called upon to lead a potential air campaign against North Korea should the situation escalate to the point of using military force, experts say.
Western analysts said it is more likely the truck was one of about half a dozen vehicles obtained years ago from China, which North Korea has modified since then.
A solid-fuel system for an ICBM would be a significant development and could allow the North Koreans to transport and launch a missile more quickly, compared to a liquid-fuel system that requires lengthy preparation.