SEOUL, May 27, 2025 (BSS/AFP) - South Korean authorities have imposed travel bans on two former acting presidents as part of an investigation into ex-leader Yoon Suk Yeol's December martial law bid, Yonhap news agency said Tuesday.

"Police said on May 27 that former prime minister Han Duck-soo and former finance minister Choi Sang-mok have been banned from leaving the country as they are being investigated as suspects in an insurrection case," Yonhap reported, adding the ban came into effect in mid-May.

Yoon was formally stripped of office last month after being impeached and suspended by lawmakers over his December 3 attempt to subvert civilian rule, which saw armed soldiers deployed to parliament.

He is currently on trial on insurrection charges over that declaration.

If found guilty, Yoon would become the third South Korean president to be found guilty of insurrection -- after two military leaders in connection with a 1979 coup.

For charges of insurrection, Yoon could be sentenced to life in prison or the maximum penalty: the death sentence.

South Koreans go to the polls next week to elect Yoon's successor, capping months of political turmoil since the martial law declaration.

Career bureaucrat Han had been touted as a possible candidate to replace him.

The ruling People Power Party (PPP) this month was forced to backtrack after trying to revoke former labour minister Kim Moon-soo's candidacy in favour of Han.