US President Donald Trump on Monday warned North Korea that the "era of strategic patience is over."

At a joint news conference with South Korean President Hwang Kyo-Ahn, US VIce President Mike Pence said, "Since 1992, the United States and our allies have stood together for a denuclearized Korean Peninsula.

"But the era of strategic patience is over. President Trump has made it clear that the patience of the United States and our allies in this region has run out and we want to see change. We want to see North Korea abandon its reckless path of the development of nuclear weapons, and also its continual use and testing of ballistic missiles is unacceptable.

"We hope to achieve this objective through peaceable means. But all options are on the table.

"North Korea would do well not to test his resolve — or the strength of the armed forces of the United States in this region."

When asked for his message for North Korean leader Kin Jong-un, Trump said two words: "Gotta behave."