A former high-ranking official in the North Korean regime said Wednesday that dictator Kim Jong Un's recent overtures to South Korea have come out of fear that the U.S. will launch a preventative strike against him.

According to Yonhap News, Ri Jong Ho -- who defected to South Korea in 2014 and moved to the U.S. in 2016 -- told a forum at the Wilson Center in Washington that Kim is "trying to buy time to complete his nuclear and missile programs."

Before his defection, Ri worked for Office 39 of the ruling Workers' Party of Korea. Despite the shadowy-sounding name, the outfit had a very clear mission: to raise money for the North Korean regime, even in defiance of United Nations sanctions.

Ri spoke Wednesday in the wake of a three-day visit to South Korea by Kim Yo Jong, Kim Jong Un's sister, during which she sat among world dignitaries -- including Vice President Mike Pence -- for the opening ceremonies at the Winter Olympics.

"Kim Jong Un is struggling under the strongest-yet sanctions and military and diplomatic pressure, so he is trying to improve the situation by putting on a false front," said Ri, who also praised the Trump administration's push to highlight human rights abuses by the Pyongyang government.

Ri's comments on sanctions appeared to strike a different tone from one he set in a Washington Post article published this past July. At that time, he described sanctions against North Korea as "perfunctory."

"We were never in pain or hurting in our trade business because of the sanctions," he told the Post at the time. "Instead, we conducted our first nuclear test in 2006."

Ri also told the paper that "unless China, Russia and the United States cooperate fully to sanction North Korea, it will be impossible to hurt [the Kim dynasty]."

On the same day that Ri spoke, U.S. Navy Adm. Harry Harris --the senior officer overseeing military operations in the Pacific -- told lawmakers that Kim's ultimate goal was to reunify the Korean Peninsula under his rule.

"I do think that he is after reunification under a single communist system," Harris told the House Armed Services Committee. "So he's after what his grandfather failed to do and his father failed to do and he's on a path to achieve what he feels is his natural place."

Click for more from Yonhap News.

The Associated Press contributed to this report.