Following a failed ballistic missile test by North Korea Sunday, Vice President Mike Pence warned that the United States' long-standing policy toward the region would change. In a visit to South Korea Monday, Pence said the "era of strategic patience" was over.

"Since 1992, the United States and our allies have stood together for a denuclearized Korean Peninsula," Pence said Monday during a news conference in Seoul, South Korean, alongside South Korean President Hwang Kyo-Ahn. "We hope to achieve this objective through peaceable means. But all options are on the table." 

"Strategic patience" as a policy has been rather vague and difficult to define. The Obama-era policy "suggested that the United States could afford to wait for North Korea to make its decision to denuclearize," according to the Council on Foreign Relations, an independent think tank.

Read: Can North Korea's Nuclear Missiles Hit The United States?

White House press secretary Sean Spicer described it as a policy of "wait and see" during a press conference Monday.

Pence described the policy in further detail during an interview with CNN's Dana Bash Monday.

"It was the policy of the United States of America during prior administrations to practice what they called 'strategic patience,' and that was to hope to marshal international support to bring an end to the nuclear ambition and the ballistic missile program of North Korea," said Pence. "That clearly has failed and the advent of nuclear weapons testing, the development of a nuclear program, even this weekend to see another attempt at a ballistic missile launch all confirms the fact that strategic patience has failed."

Read: Where Are The World's Nuclear Weapons?

During the press conference in Seoul, Pence cautioned North Korea "not to test" the resolve or strength of the U.S., and noted that "all options" were on the table.

"I think that, as the president's made clear, we're going to abandon the failed policy of 'strategic patience' but we're going to redouble our efforts to bring diplomatic and economic pressure to bear on North Korea," Pence told Bash. "Our hope is that we can resolve this issue peaceably."

RTS12L7C-2 Vice President Mike Pence shakes hands with South Korean President and Prime Minister Hwang Kyo-ahn in Seoul, South Korea, Apr. 17, 2017. Photo: Reuters