South Korean police searched President Yoon Suk Yeol's office Wednesday over his imposition of martial law last week, reports said, as some of his top officials were arrested, detained and questioned about their actions in enforcing his orders.

The developments come hours before the main liberal opposition Democratic Party submits a new motion to impeach Yoon as the country's main law enforcement institutions expand their investigations into whether the president's declaration amounted to rebellion. The first impeachment attempt failed last Saturday when the ruling party boycotted the vote. The Democratic Party said it aims to put the new motion to a vote on Saturday.

Yonhap news agency reported that police are searching Yoon's office but gave no further details. Police and Yoon's office didn't immediately confirm the report.

The country's main law enforcement institutions are focusing on finding whether Yoon and others involved in imposing martial law committed the crime of rebellion.

Court approved ex-minister's arrest

Earlier Wednesday, Yoon's former defence minister, Kim Yong Hyun, was arrested after a Seoul court approved a warrant for him on allegations of playing a key role in a rebellion and committing abuse of power. Later in the day, National Police Agency Commissioner General Cho Ji Ho and Kim Bong-sik, head of the metropolitan police agency of Seoul, were detained over their actions during martial law.

They are being investigated for their roles in deploying police forces to the National Assembly to block lawmakers from voting to lift Yoon's martial law decree.

On Wednesday, Shin Yong Hae, commissioner general of of the Korea Correctional Service, told lawmakers that Kim tried to kill himself at a detention centre in Seoul. He said that Kim's suicide attempt failed after centre officials stopped him and that he is in a stable condition now.

At the same parliament committee meeting, Justice Minister Park Sung Jae confirmed Kim's failed suicide attempt.

Yoon's power grab has paralyzed South Korean politics, frozen its foreign policy and rattled financial markets, greatly reducing his chances of completing his five-year term and casting a turbulent shadow over one of Asia's most robust democracies.

After last week's impeachment motion fell through, the leader of Yoon's conservative party pledged to arrange his stable exit from power, saying the party will co-ordinate with cabinet members over state affairs and that Yoon will be sidelined from duties during a transition to an early election.

However, the plans have been widely criticized as unrealistic and unconstitutional. The constitution explicitly states that impeachment is the sole method for suspending presidential powers and that the authority to command the military rests solely with the president. The defence ministry said this week that Yoon remains in charge of the country's military forces.

Troops deployed on minister's orders: commanders

The Assembly was also encircled by heavily armed troops, which military commanders say were deployed on the orders of the former defence minister. But enough lawmakers eventually managed to enter a parliament chamber and unanimously rejected Yoon's decree, forcing the cabinet to lift it before daybreak on Dec. 4.

During a parliamentary hearing Tuesday, Kwak Jong-keun, commander of the Army Special Warfare Command whose troops were sent to parliament, testified that he received direct instructions from Kim Yong Hyun to obstruct lawmakers from entering the Assembly's main chamber. Kwak said the purpose of Kim's instructions was to prevent the 300-member parliament from gathering the 150 votes necessary to overturn Yoon's martial law order.

Kwak said Yoon later called him directly and asked for the troops to "quickly destroy the door and drag out the lawmakers who are inside." Kwak said he discussed Yoon's order with the commander at the scene and that they concluded there was nothing that could be done, ruling out the possibility of threatening the lawmakers by shooting blanks or cutting off electricity.

At the same hearing, senior officer Kim Dae-woo of the military's counterintelligence agency said his commander, Yeo In-hyung, asked him if an army bunker in Seoul had space to detain politicians and other figures after martial law was imposed. Yeo is considered a close associate of Kim Yong Hyun. Last week, Hong Jang-won, a deputy director of the country's spy agency, said Yoon ordered him to help Yeo's command to detain some of his political rivals but he ignored the president's order.

Kwak and Yeo are among those who face opposition-raised rebellion charges along with Yoon and Kim, and the defence ministry suspended them last week.