South Korean President Yoon Suk-yeol skipped the ninth hearing of his impeachment trial on Tuesday as his legal team clashed with lawyers representing the National Assembly over evidence examination.

Yoon arrived at the Constitutional Court but left for the Seoul Detention Center before proceedings began, Yonhap News Agency reported.

"After consulting with the legal representatives, it was confirmed that today's hearing involves summarizing the current situation while allowing the legal teams of both sides to present their arguments," Yoon's legal team stated. "As such, President Yoon returned to the detention center."

With no need for Yoon to directly present his opinions, he entrusted the matter to his legal team to ensure the smooth progress of the trial, his lawyers said.

Yoon faces impeachment over his short-lived martial law declaration on Dec 3 and has attended hearings since the third session on Jan 21.

During Tuesday's hearing, the National Assembly's legal team-serving as a prosecutor — and Yoon's side were each given two hours to summarize their arguments and present key evidence.

The National Assembly presented excerpts from the prosecution's interrogation of Cho Ji-ho, commissioner general of the National Police Agency.

According to Cho's testimony, Yoon had instructed him to detain all National Assembly members entering the building after he declared the martial law.

In addition, the National Assembly disclosed other investigation records related to the martial law decree, and testimonies from Cabinet members who attended the meeting convened by Yoon before the declaration.

In response, Yoon's legal representative Cho Dae-hyun said the use of testimony from individuals who had not appeared in court as witnesses is against the law, and their credibility cannot be cross-examined by Yoon's side.

"I request that they be excluded from the evidence examination," Cho Dae-hyun said.

Yoon's legal team also denied that he ordered the arrest of lawmakers and defended the necessity of martial law.

On Monday, Kwon Young-se, interim leader of the ruling People Power Party, criticized the Constitutional Court, accusing it of "rushing to make a judgment without careful deliberation".

Kwon said that while investigators summoned 520 people for questioning, the court said it could determine the whole story of martial law based on testimony from just 14 witnesses, Yonhap reported.

'Clearly a mistake'

Kwon called for a fair trial for Yoon but acknowledged that the martial law declaration was "clearly a mistake".

The final scheduled hearing is set for Thursday. Despite Yoon's request for a postponement because of a preparatory hearing for his criminal trial on charges of insurrection on the same day, the court has decided that the date will remain unchanged.

Impeached Prime Minister Han Duck-soo, National Police Agency's Cho Ji-ho, and former first deputy director of the National Intelligence Service Hong Jangwon are set to testify in the 10th hearing.

In an impeachment trial, once all witnesses have testified and all evidence has been examined, the court hears final statements from both sides before concluding proceedings.

Unless an additional hearing is scheduled, the Constitutional Court is widely expected to issue its verdict next month on whether to uphold the impeachment.

A survey published by Gallup Korea found that 57 percent of South Koreans supported Yoon's impeachment, while 38 percent opposed it.

Supporters of impeachment cited reasons such as the martial law declaration, charges of insurrection, Yoon's inability to manage state affairs, and the chaos and instability in the country.

Opponents, on the other hand, pointed to the opposition party's obstruction and impeachment attempts, as well as the legitimacy of martial law as part of the president's inherent authority.

kelly@chinadailyapac.com