South Korea's Defense Minister Lee Jong-sup reportedly expressed his intention to resign on Tuesday, amid increasing demands from the opposition to remove him, citing allegations of his interference in a probe into the death of a Marine.

Lee, a 63-year-old retired Army lieutenant general who has served as the defense minister since President Yoon Suk Yeol's inauguration in May 2022, expressed his intent during a Cabinet meeting at Yoon's office on Tuesday, according to news reports citing an unnamed government official.

An official of the presidential office on Tuesday declined to comment on this matter, saying further explanation will be made in the upcoming Cabinet reshuffle later this week if Yoon has Lee replaced.

Lee told terrestrial broadcaster KBS that he feared the "pressure that the government had to bear" due to an anticipated leadership void in South Korea's national defense mechanism if he were to stick to his post and his impeachment motion passed the parliament, forcing his suspension from the position.

Under Korean rules, an impeached Cabinet member is temporarily deprived of his or her role and the post must remain vacant until the binding Constitutional Court ruling. The member can return to the post if the court rejects the National Assembly's motion.

Lee is alleged to have urged Marines to hold off on the investigation into an incident where Cpl. Chae Su-geun was swept away and found dead 14 hours later during a rescue operation as Korea was hit by a heavy downpour in July.

Marine Col. Park Jung-hun, who was leading the probe, refused to heed Lee's request, which resulted in the ministry's decision to dismiss Park and sue him for alleged insubordination.

The main opposition Democratic Party of Korea sees Lee's move as interference into a probe to determine accountability for Chae's death.

Democratic Party lawmakers called on the government to sack Lee, threatening otherwise that they would propose a motion to impeach him. The party was to file the motion Tuesday.

Lee has been facing criticism over the ministry's stance toward independence fighter Hong Beom-do during the Japanese colonial era in the early 20th century that has questioned his alleged communist affiliation. Lee upped the ante by commenting that the ministry was considering removing Hong's name from a Navy submarine that bears it.