SEOUL -- A close ally to North Korean leader Kim Jong Un now reportedly occupies a powerful post that confers control over appointments and information in the secretive state's ruling party -- a position that Kim's father held as a power base.

The move may be significant, for Kim has until now avoided any appointments that would point to a clear No. 2 within the regime.

South Korea's Unification Ministry said Thursday it had confirmed that Choe Ryong Hae, vice chairman of the Workers' Party of Korea Central Committee, has become director of the party's organization and guidance department.

This department has been described as the "party within the party." Kim's father Kim Jong Il held the directorship himself during his time as North Korean leader, and it had been vacant since his death in 2011. Some observers had speculated the younger Kim had quietly taken over the position himself.

Choe, who rose through the party bureaucracy, is the son of a partisan who fought against Imperial Japan alongside Kim's grandfather Kim Il Sung, the founder of North Korea. That makes Choe part of a generation of princelings. While it remains unclear whether his new appointment to a powerful post means he has emerged as the younger Kim's most trusted ally, that Choe's influence has grown even larger seems certain.

Kim has promoted or demoted figures at will since taking power, in an apparent effort to stave off any moves to depose him.

Purge leader out as security chief

In other personnel developments, Kim Won Hong has been replaced as minister for state security by Jong Kyong Thaek, according to the South's Unification Ministry. This post oversees North Korea's feared secret police. Little about Jong's career is known, but he appears to be a member of Kim Jong Un's circle of allies.

Kim Won Hong led the 2013 purge of Kim's uncle Jang Song Thaek and, for a time, was seen as rivaling Choe in influence. But the Unification Ministry reported that the security chief was dismissed in January 2017 for misdeeds including corruption and human rights abuses. According to South Korea's National Intelligence Service, Kim Won Hong may have been punished along with military political affairs chief Hwang Pyong So, who had been close to the leader.

The party's organization department launched a penetrating investigation of the State Security Ministry, accusing it of arrogance toward the party, according to the South's spy agency. Choe is believed to have orchestrated these moves in a power struggle against enemies.

Meanwhile, the head of the North Korean delegation to Tuesday's talks with South Korea, Ri Son Gwon, now holds a seat on the Foreign Affairs Committee of the North's parliament, according to the Unification Ministry.