The prosecution has arrested former Defense Minister Kim Yong-hyun in a probe into President Yoon Suk Yeol's martial law declaration and his alleged treason.

The prosecution's special investigation headquarters said on Sunday that they arrested Kim without a court warrant at around 7:50 a.m. and transferred him to the Dongbu detention center in southern Seoul.

The prosecutors said they also seized Kim's mobile phone.

The emergency arrest came about six hours after Kim voluntarily appeared at the Seoul Central District Prosecutors' office for overnight questioning at 1:30 a.m.

According to the Criminal Procedure Act, the prosecution can arrest a suspect without a warrant if it determines that the suspect is likely to destroy evidence or flee.

Kim, who is believed to have advised Yoon to declare emergency martial law on Tuesday night, is facing charges of treason and abuse of authority.

President Yoon lifted martial law six hours after the National Assembly voted to end it, and Kim submitted his resignation on Wednesday, which Yoon accepted on Thursday.