Trump and China working on ‘Korea problem’
There was speculation that China could cut off imports of oil from North Korea.
Mr Trump’s comments came after a North Korean missile exploded during launch.
It was launched just a day after the country staged one of its biggest propaganda exercises by parading weapons to mark the 105th birthday of late North Korea founder Kim Il Sung, the current leader’s grandfather.
The North’s test firing was being seen as a message of defiance to Mr Trump the day after vice president Mike Pence is set to arrive in Seoul for talks on North Korea.
A US aircraft carrier sits off the Korean Peninsula in a show of force.
In a statement, US Defense Secretary Jim Mattis said Mr Trump and his military team “are aware of North Korea’s most recent unsuccessful missile launch. The president has no further comment.”
Many analysts believe that North Korea has not yet mastered the technology to build warheads small enough to place on long-range missiles.
Mr Pence was joined in South Korea by his wife and two adult daughters and was laying a wreath at the Seoul National Cemetery at the start of his trip. He is expected to join US and South Korean troops for Easter Sunday church services and a dinner later in the day.
Mr Trump has suggested that the US will take a tougher stance against the North Korean threat.
“North Korea is a problem. The problem will be taken care of,” he told reporters.