Jang Song Thaek, the uncle and de facto deputy of North Korean leader Kim Jong Un, is safe even as it appears he has been removed from his post, a South Korean minister said.

Jang, a vice chairman of the National Defense Commission led by Kim, remains physically unharmed, Unification Minister Ryoo Kihl-jae told a parliamentary hearing Wednesday in Seoul, local television networks reported. The Unification Ministry later confirmed the remarks.

“Purges are continuing in North Korea,” Ryoo told lawmakers, without saying how he obtained the information.

The removal of Jang, which would be the highest-level dismissal since Kim took power two years ago, may indicate that Kim is still trying to solidify his grip on power by dismissing officials who gained prominence under his late father, Kim Jong Il. In October, Kim replaced his chief of general staff for a third time since taking over the North’s 1.2 million-strong army after his father died of a heart attack in 2011.

Jang hasn’t been seen since the public execution of two of his confidants last month, South Korea opposition lawmaker Jung Cheong Rae said by phone Tuesday, citing the South’s National Intelligence Service. Ruling party lawmaker Cho Won-jin said at a televised briefing that the purge followed a corruption investigation. Both Jung and Cho serve on South Korea’s parliament intelligence committee. The NIS declined comment on Jang when a call was made to its main phone number Tuesday.

“This could be a sign there’s a problem with Kim Jong Un’s grip on power,” Ahn Chan-il, who heads the World Institute for North Korea Studies in Seoul, said by phone. “I suspect there is a stability issue in the regime.”

Jang, who married Kim Jong Un’s aunt, Kim Kyong Hui, in 1972, was named to the post in June 2010 by Kim Jong Il.

North Korea is “conducting follow-up measures” against organizations affiliated with Jang, lawmaker Cho said. The government is mounting a campaign for “absolute loyalty” to Kim, he said.

Some defense-related stocks gained Wednesday in Seoul. Speco Co., a maker of fin stabilizers and water jets, gained 5.7 percent, the biggest rise since Oct. 4. Victek Co., a manufacturer of electronic warfare equipment, rose 2.2 percent. Armored vehicle maker Firstec Co. fell 0.3 percent after rising as much as 5.9 percent earlier in the day.

During Kim Jong Il’s rule, the National Defense Commission was regarded as North Korea’s most powerful institution, and remains more important than both the nation’s defense agency and the ruling Korean Workers’ Party. Jang walked directly behind Kim Jong Un at his father’s funeral.

“Kim is warning the public with the executions, and it can only mean he’s feeling insecure about his power,” said Lee Ji-sue, a professor of North Korean studies at Myongji University in Seoul. “Kim just didn’t have enough time to build his own power base before his father died, and the economic situation right now just doesn’t help.”

Jang, one of the country’s leading economic policymakers who visited China in August last year, was reported by South Korean newspapers to have been demoted in 2004 for cultivating too much influence. He was brought back to power in 2006 to head the Workers’ Party administrative department, overseeing the intelligence agency and other military institutions.

The disappearance of a senior official instrumental to Kim Jong Un’s succession isn’t unprecedented. In 2012, North Korea’s official Korean Central News Agency said that Ri Yong Ho, the general staff chief, had been removed from all posts, while all traces of his presence were eliminated from official footage and photos. KCNA gave no clear reason for the decision.

KCNA last reported on Jang in early November.

A corruption investigation into Jang’s allies may have been led by Choe Ryong Hae, North Korea’s top political military officer, as a result of a power struggle, and may actually show Kim’s strength, Cheong Seong-chang, a researcher at the Seongnam-based Sejong Institute, said in an email.

“The executions and Jang’s removal from posts show Kim Jong Un’s power is very solid at the moment,” Cheong said. “I expect the race for loyalty will heat up in the ruling circle in the future.”

North Korea’s relations with the outside world have dimmed under Kim, as the country tested its third atomic device in February and threatened nuclear strikes against South Korea and the U.S. On Nov. 6, North Korea rejected the idea of a summit after South Korean President Park Geun-hye said she was willing to meet Kim if it led to concrete results.

The two Koreas remain technically in conflict after the 1950-53 Korean War ended without a formal peace treaty.

“Instability with Kim’s grip on power will continue, and he may try to ride it out by creating a military crisis with the outside world,” Myongji University’s Lee said. “With no aid and no dialogue, the crisis for the ruling class continues to deepen.”