Following the unsuccessful attempt, Kim is being held in a protective cell and his health remains stable, Shin Yong-hae, the head of the correctional center, told lawmakers as quoted by Yonhap news agency during a parliamentary hearing.

Kim Yong-hyun resigned last week following President Yoon Suk Yeol's failed attempt to impose martial law in the fourth-largest economy in Asia.

The former Minister was arrested on Tuesday for further investigation.

He is the first top Minister of the nation who was arrested in connection with the incident.

Thousands of people took to the streets of South Korea to protest against the President's short-lived attempt to impose the law, a move that dragged the nation into crisis and triggered a major political crisis in decades.

Police raid presidential office

Meanwhile, police on Wednesday raided the presidential office and the police headquarters as part of the probe into the brief imposition of martial law last week.

Raids were also being conducted at the offices of the Seoul Metropolitan Police and the National Assembly Police Guards, police told Yonhap.

The President was reportedly not present in his office when police conducted the raid.

What happened in South Korea last week?

During his unannounced television address, President Yoon Suk Yeol declared the imposition of martial law on December 3 when he also accused the main opposition party of sympathizing with North Korea and of “anti-state activities.”

However, the President reversed his order in just six hours after lawmakers forced their way to the Parliament to strike down the decree.

Since then the President has been facing intense pressure to step down.

Amid severe protests against him, the President survived an impeachment attempt on Saturday after his ruling conservative People Power Party left parliament and boycotted the vote.

South Korea's main opposition Democratic Party is preparing to bring another impeachment motion against the President.

Voting may take place on Saturday.