Opposition politicians are raising the possibility of impeaching President Yoon Suk Yeol as they push for a bill to investigate his alleged meddling in the investigation of a soldier's death.

Opposition parties, which hold a strong majority in South Korea's National Assembly, plan to reintroduce a bill to launch a special counsel probe of alleged interference in a Marine Corps internal investigation following the death of a Marine last summer.

On Monday, Rep. Jang Kyung-tae, an outspoken two-term lawmaker of the Democratic Party of Korea, said in the party leadership's meeting that the president could be subject to impeachment if he is found to have exerted influence over the Marine Corps' internal probe. He said evidence suggested that Yoon had been involved in the government's attempt to confiscate probe records from the South Korean Marine Corps.

Earlier on Friday, Democratic Party Rep. Jeon Hyun-heui said at the National Assembly that evidence of Yoon's interference in an ongoing probe could "lead to the impeachment of Yoon, as he is accused of abuse of power."

The main opposition lawmakers were referring to Yoon's alleged interference in the Marine Corps' probe into the death of a Marine during a rescue operation in a flooded area, which was one of the five reasons why a parliamentary petition called on the National Assembly to dethrone Yoon through an impeachment motion.

The petition on the National Assembly's web portal had drawn over 100,000 signatures as of Monday morning, four days after it was made public. A parliamentary petition on the web portal that gathers 50,000 signatures within a month begins to go through legislative steps.

In nearly 70 years of modern history, two South Korean presidents have been impeached by the National Assembly, namely the late liberal Roh Moo-hyun and former conservative president Park Geun-hye. Park's impeachment was confirmed and she was removed from the office of president by the Constitutional Court in 2017, but the court rejected Roh's.

Yoon's political opponents believe he may have interfered in the investigation to stop a Marine Corps commander from being blamed after an internal probe that found the commander responsible for Cpl. Chae Su-geun being insufficiently equipped during the rescue operation in July last year. Chae was swept away in floodwater during the operation.

Also during Monday's meeting, four-term lawmaker Seo Young-kyo urged the investigative authorities to carry out a search and seizure against Yoon and his secretaries. Rep. Kim Seung-won, a two-term lawmaker of the main opposition, said in a press conference later Monday that the phones of Yoon and his secretaries must be obtained to prevent them from destroying evidence.

The same special bill unilaterally proposed by the opposition bloc was vetoed by Yoon in May, just a week before the previous term of the National Assembly wrapped up.

On Saturday, Rep. Cho Kuk, who chairs the liberal minor opposition Rebuilding Korea Party, said in a meeting with party members in Daejeon that a majority of the people complain that three months in a term would be too much left for Yoon, much less three years.

Yoon, who started his presidency in May 2022, has about three years left until his five-year term ends in May 2027.

Meanwhile, a poll released Monday by Realmeter indicated that Yoon's approval rating remained in the low-30 percent range for the 11th consecutive week. The latest figure stood at 32.1 percent, up 2 percentage points from a week prior.