WASHINGTON (Reuters) - The United States is open to talks with North Korea, but only to convey the U.S. stance that “the most tyrannical and oppressive regime on the planet” must give up its nuclear weapons, U.S. Vice President Mike Pence said on Wednesday.

Pence told the Axios news outlet in an interview the United States would continue to intensify diplomatic and economic pressure on North Korea and that the sanctions would not be lifted until it abandoned its weapons programs.

“We want to make sure North Korea understands us, and if there’s an opportunity for talks that can communicate the fixed policy of the United States of America to them, the president has made it clear he always believes in talking. But talking is not negotiation – talking is understanding one another,” he said.

Pence spoke after attending the Winter Olympics in South Korea last week, at which he avoided contact with a North Korean delegation that held talks with the South Korean leadership.

Pence was widely seen as having been outplayed by a “charm offensive” by the North Korean delegation, which included North Korea leader Kim Jong Un’s sister Kim Yo Jong.

Pence said he did not greet the delegation given that North Korea’s was “the most tyrannical and oppressive regime on the planet.”

“I didn’t avoid the dictator’s sister, but I did ignore her,” he said. “I didn’t believe it was proper for the United States of America to give any countenance or attention in that forum to someone who is not merely the sister of the dictator, but is the leader of the propaganda effort.”

Pence called North Korea a “prison state” and accused the ruling family of widespread abuses, including the murder of Kim Jong Un’s brother and uncle.

“This is evil the likes of which we have witnessed rarely in our time around the world. And I wanted to send by my silence a very clear message that the people of the United States of America know who we’re dealing with,” he said.

South Korea says its president, Moon Jae-in, who has been pushing for a diplomatic solution to the standoff over North Korea’s development of nuclear weapons capable of hitting the United States, was offered a meeting with Kim in Pyongyang via his sister.

The North-South thaw has prompted speculation that it could lead to direct talks between Washington and Pyongyang after months of tension and exchanges of insults between U.S. President Donald Trump and Kim, which has fueled fears of war.

Pence told Axios that regardless of the North-South talks, there was “no daylight” between the allies on the need to intensify pressure on Pyongyang.

“We will all remain united in our shared commitment that the Kim regime in North Korea must permanently abandon their nuclear weapons program to see it dismantled, to accept denuclearization before there is any progress whatsoever on the pressure on the sanctions,” he said.

Also on Wednesday, the head of the U.S. Pacific Command, Admiral Harry Harris, stressed the threat posed by North Korea at a congressional hearing and said Pyongyang was clearly engaged in a “charm offensive” toward the South.

“I think it behooves us and our Korean allies not to be charmed (and) consider North Korea for the regime it is and deal with it on the basis of fact, not charm,” he told the House of Representatives Armed Services Committee.