Kim Yo-jong, sister of North Korean leader Kim Jong-un, appears to have been promoted to a leadership role, South Korea's spy agency said Tuesday.

The status of Kim Yong-chol, who served as a chief negotiator in nuclear talks with the United States, also seems to have fallen, following the no-deal summit between the North's leader and US President Donald Trump, the National Intelligence Service (NIS) said in a closed-door briefing to lawmakers.

Kim Yo-jong, who has assumed the No. 2 post of the ruling Workers' Party of Korea's propaganda and agitation department, was spotted sitting next to Kim Yong-chol to watch the country's propaganda performance last week, an event to celebrate Chinese President Xi Jinping's visit to the North.

"She appears to have been promoted to the leader level. Her status seems to have been raised following a role adjustment," the NIS was quoted as saying by Rep. Lee Hye-hoon.

Rumor had it that she was disciplined in the wake of the breakdown of the Kim-Trump summit in February in Vietnam as Kim disappeared for more than two months from public view.

But trumping such a speculation, she returned to the public eye in early June when attending the propaganda group gymnastics and artist performance.

The NIS said she appears to be on the same level as Choe Ryong-hae, de facto No. 2 man in the country, and Ri Su-yong, vice chairman of the WPK.

"Choe is definitely playing the role of No. 2," it added.

The NIS said the foreign ministry is apparently taking a leading role in dealing with external relations, including nuclear negotiations with the US.

Rep. Lee said Hyon Song-wol, head of the North's Samjiyon Orchestra, is assuming Kim Yo-jong's previous duty of handling protocol for the North's leader.

Kim Jong-un and Xi may have discussed ways to bolster economic and military cooperation during their summit in Pyongyang.

Xi visited North Korea on Thursday and Friday for his summit with Kim to discuss the North's denuclearization and bilateral ties. It was made to reciprocate Kim's trips to China on three occasions last year.

The agency said Xi's trip, his first state visit to North Korea, was timed to coincide with weeks of protests in Hong Kong against an extradition bill that could deal a blow to the Chinese president's leadership.

The NIS said China's potential assistance to support North Koreans' livelihoods might have been discussed under the framework of international sanctions.

"It would be impossible to seek tourism involving a large facility investment. Assistance of food, fertilizers, crude oil and tourism may be possible even under global sanctions on North Korea," it noted. (Yonhap)