SEOUL, South Korea (AP) -- Choi Sang-mok, South Korea's former acting leader, was indicted on Thursday for his role in the brief imposition of martial law in December 2024 under then-President Yoon Suk Yeol. This development marks another escalation in the ongoing legal troubles surrounding key figures from the Yoon administration.

Choi is one of three high-ranking officials from Yoon's administration who served as caretaker presidents after Yoon was impeached and removed from office due to the martial law declaration, which thrust South Korea into significant political chaos. Currently, Yoon is incarcerated and facing a serious criminal trial on rebellion charges.

The fallout from Yoon's martial law declaration has resulted in numerous arrests, indictments, and ongoing investigations involving senior officials and military leaders associated with the former administration. Choi is specifically charged with dereliction of duty for failing to fully restore three vacant seats at the nine-member Constitutional Court, which was in the midst of deliberating the decision on whether to unseat Yoon.

Reinstating the court to its full strength could have enhanced the likelihood of Yoon's ouster, as a ruling to dismiss him required the backing of at least six justices. During his tenure as interim president, Choi, who also served as finance minister, appointed two new justices but left one seat unfilled, citing a lack of bipartisan consensus upon taking office.

In April, the Constitutional Court's eight justices unanimously ruled to remove Yoon from his position. On the same day as Choi's indictment, independent counsel Cho Eun-suk indicted another acting leader, Han Duck-soo, on similar charges of dereliction of duty. Han had previously been indicted in August on more serious charges of facilitating Yoon's martial law imposition.

Cho's team claims Han attempted to legitimize Yoon's martial law decree during a Cabinet Council meeting. However, Han has consistently maintained that he voiced opposition to Yoon's martial law plans. Additionally, five other individuals, including Yoon's justice minister, were indicted on the same day on various charges related to the martial law situation. Choi is also facing perjury allegations regarding his testimonies during Han's trial.

The investigation concerning Yoon's martial law declaration is one of three independent counsel probes aimed at Yoon, his wife, and other associates. These investigations were initiated under the new President Lee Jae Myung, who came into power following an early election in June, which was prompted by Yoon's removal.

In August, First Lady Kim Keon Hee was arrested and indicted for allegedly violating financial and political funding laws, along with accusations of accepting bribes. Hak Ja Han, the 82-year-old leader of the Unification Church, was also arrested and indicted on charges claiming she instructed church officials to bribe a senior lawmaker affiliated with Yoon.

This Unification Church scandal has created upheaval in South Korean politics, leading to speculation in local media about other politicians, including members of the Lee administration, possibly receiving illicit funds from the church. Recently, Oceans Minister Chun Jae-soo denied bribery allegations but nevertheless offered his resignation to avoid burdening the Lee administration. Lee accepted Chun's resignation later in the day.

Earlier this week, President Lee called for a comprehensive investigation into the allegations surrounding politicians and a religious organization, although he did not specifically name the Unification Church.