Prosecutors open investigation into South Korean president over martial law, Yonhap reports

South Korean prosecutors have opened an investigation into President Yoon Suk Yeol, his interior minister, and the now-former defence minister over their roles in an attempt to impose martial law, Yonhap news agency reported on Thursday.

Kim Yong-hyun, who resigned as South Korean defence minister over his involvement in Tuesday's martial law order, also faces a travel ban as prosecutors investigate, Yonhap said. The other two do not face such bans.

Citing unspecified threats from "anti-state forces" and obstructionist political opponents, Yoon imposed martial law for about six hours before reversing course after parliament voted to oppose the move.

Yoon now faces an impeachment vote on Saturday.