South Korean President Yoon Suk Yeol has been banned from leaving the country over a failed attempt at imposing martial law, a justice ministry official said on Monday, amid growing calls for him to step down and a deepening leadership crisis. Yoon has apologised for the botched attempt and said he was leaving his political and legal fate to his ruling People Power Party (PPP) but has not resigned. He has become the subject of criminal investigation, according to local media reports. On Monday, the defence ministry said Yoon was still legally commander in chief, but his grip on power has come into question with dissent growing among senior military officers against the president, and his own party saying it would establish a task force to handle his eventual resignation. Oh Dong-woon, the head of the Corruption Investigation Office for High-ranking Officials, said he has ordered a ban on foreign travel for Yoon, when asked at a parliament hearing what actions have been taken against the embattled president. A justice ministry official, Bae Sang-up, told the committee the travel ban order has been executed. The panel was established in 2021 to investigate high-ranking officials including the president and their family members but it does not have authority to prosecute the president. Instead, it is by law required to refer the matter to the prosecutors’ office. While Yoon survived an impeachment vote in parliament on Saturday, his party’s decision to delegate presidential authority to the prime minister has plunged the key US ally into a constitutional crisis. Yoon has refused calls, including some from within his own ruling party, to resign, and his future looked more uncertain over the weekend when Yonhap news agency reported he was under criminal investigation for alleged treason. Prosecutors on Sunday arrested ex-defence minister Kim Yong-hyun over his alleged role in the declaration of martial law on December 3, Yonhap reported.