Lee Jin-woo, former head of the Capital Defense Command; Yeo In-hyung, former head of the Defense Counterintelligence Command; and Hong Jang-won, former first deputy director of the National Intelligence Service, have been called to testify at the trial's fifth formal hearing at the Constitutional Court at 2 p.m.

The Constitutional Court has approved the spy agency chief and top security adviser as witnesses to testify at the impeachment trial of President Yoon Suk Yeol, a court official said Friday. National Intelligence Service (NIS) Director Cho Tae-yong and National Security Adviser Shin Won-sik will be

South Korean President Yoon Suk Yeol denied wrongdoing as he branded himself as a firm believer in democracy in his first appearance at an impeachment trial looking into his shocking and brief imposition of martial law last month.

South Korean President Yoon Suk-yeol has made his first court appearance in the trial to determine the validity of his impeachment over his brief declaration of emergency martial law in December.

Suspended President Yoon Suk Yeol will attend the fourth hearing of his impeachment trial on Thursday, his lawyers said, as former Defense Minister Kim Yong-hyun is slated to appear and testify as well.

The Constitutional Court warned that questioning the political inclinations of individual justices could "distort the trial’s nature and infringe upon judicial authority."

South Korea’s Constitutional Court will hold full-day hearings for President Yoon Suk-yeol’s impeachment trial from 10 a.m. next month. Previously, hearings began at 2 p.m. and lasted three to four hours,