SEOUL -- North Korean leader Kim Jong Un's sister is emerging as a candidate to visit the U.S. for talks with Secretary of State Mike Pompeo, who has invited a senior Pyongyang official to Washington.

Kim Yo Jong, who is said to have a close relationship with her brother, could play key roles in setting up a summit between Kim Jong Un and U.S. President Donald Trump as well as in narrowing differences between the countries regarding the denuclearization road map.

The siblings studied together in Switzerland when they were teenagers.

"We cannot rule out the possibility that it will be Kim Yo Jong," said Yang Moo-jin, a senior professor of the University of North Korean Studies in Seoul. "She accompanied Chairman Kim to the inter-Korean summit in September and during Pompeo's fourth visit to Pyongyang [in early October], while Kim Yong Chol and Ri Yong Ho were excluded."

In May, Kim Yong Chol, a vice chairman of the Workers' Party of Korea, met with Pompeo in New York to discuss the first Kim-Trump summit. Foreign Minister Ri had a meeting with Pompeo last month in New York while the United Nations' General Assembly was in session.

Yang said the North Korean leader's sister could try to influence Trump through an intermediary -- Ivanka Trump, the president's daughter.

Kim Yo Jong was described as the "North Korean Ivanka" when she visited South Korea in February for the Winter Olympics in Pyeongchang, east of Seoul.

"If North Korea sends Kim Yo Jong to the U.S.," said Paik Hak-soon, president of the Sejong Institute think tank, "Pyongyang would be sending a clear message [that it wishes] to help President Trump [in the midterm elections]. It would also be a gesture meant to pressure the U.S. to make progress toward the agreements it made in Singapore more quickly and clearly."

The first Kim-Trump summit was held in June in Singapore.

Pompeo on Friday suggested that a senior North Korean official come to Washington soon to discuss plans for the second summit, negotiations for which are at a stalemate.

"I'm very hopeful we'll have senior leader meetings here in the next week and a half or so between myself and my counterpart to continue this discussion so that when the two of them get together there's real opportunity to make another big step forward on denuclearization," Pompeo said in an interview with Voice of America.

Trump and Kim agreed to meet after their first encounter but are struggling to fix a date and venue. Trump said the meeting could come after the midterm elections, on Nov. 6, while John Bolton, Trump's national security adviser, said the summit could be a couple of months away.