President Trump has told North Korea's leader he must 'behave' - a day after the country's failed missile test.
He made the comments at the White House while his vice president was on a visit to South Korea.
Mike Pence, meanwhile, has warned America's "era of strategic patience is over", and says North Korea shouldn't test Donald Trump's resolve.
Pyongyang's deputy ambassador to the UN, Kim In Ryong, had this to say in return: