He also warned that North Korea, which will participate in this month's Winter Olympics as part of a joint delegation with South Korea, would not be allowed to "hijack" the event with its "propaganda".

"I'm announcing today that the United States will soon unveil the toughest and most aggressive round of economic sanctions on North Korea," Pence said, standing alongside Shinzo Abe after talks on the threat posed by Pyongyang.

"Let the world know this: We will continue to intensify our maximum pressure campaign until North Korea takes concrete steps towards complete, verifiable and irreversible denuclearisation," he added.

President Donald Trump has criticised the policy of previous US administrations towards North Korea and has already convinced the global community to significantly tighten sanctions against Pyongyang.

But so far, China has failed to agree to a game-changing oil embargo, and there remains fierce debate inside the White House on whether pre-emptive military action will be needed to stop North Korea's drive for nuclear power status.

Pence stressed Wednesday that "all options are on the table" and pledged that Washington would continue to deploy some of its "most advanced military assets to Japan and the wider region" to protect against the threat posed by North Korea.

Abe, who like Pence will travel to South Korea's Pyeongchang for the Winter Games, said he had told the US vice president: "We can never accept a nuclear-armed North Korea."

"We shouldn't be captivated by the charm offensive of North Korea," he added.

North and South Korea have, at least temporarily, put aside their enmity to allow Pyongyang to send athletes to the Games, an opening that some see as an opportunity to push for a negotiated settlement.

But Pence warned that North Korea would not be allowed to instrumentalise the Games.

"We will not allow North Korean propaganda to hijack the message and imagery of the Olympic Games," he said.

"We will not allow North Korea to hide behind the Olympic banner the reality that they enslave their people and threaten the wider region."