President Yoon Suk Yeol's defense team expressed "extreme regret" after the Constitutional Court dismissed a petition to exclude Justice Chung Kye-sun from the president's impeachment trial.

Following the first hearing for argument of merits in the case on Tuesday, Yoon Kap-keun, one of the lawyers, said rejecting the petition without a valid reason goes against legal principles, fairness or common sense.

While the dismissal can not be appealed, Yoon said the team intends to call on Chung to voluntarily recuse herself.

Yoon's team filed the petition the previous day, raising concern over Chung's membership to a group of progressive-minded judges.

The court also turned down the team's objection against the court's scheduling of hearings without collecting an opinion from the defense, which the team said overstepped its authority.

Meanwhile, the National Assembly's impeachment team criticized the president for being "hostile toward the Constitution," after he was absent from Tuesday's hearing.