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 growing dissent among senior military officers against the president has thrown into question his grip on power.

Oh Dong-woon, the head of the Corruption Investigation Office for High-ranking Officials, said he had barred Yoon from foreign travel when asked at a parliament hearing what actions have been taken against the president.

A justice ministry official, Bae Sang-up, told the committee the travel ban order had 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, but 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.

Yoon gave the military sweeping emergency powers on December 3 to root out what he called “anti-state forces” and obstructionist political opponents. He rescinded the order six hours later after parliament voted against the decree.

Amid the backlash, multiple military officials, including the acting defence minister, have said they would not follow any new order to impose martial law again.

The main opposition Democratic Party (DP) has called for Yoon to be stripped of his authority over the military. The DP has also demanded the arrest of Yoon and any military officials implicated in the martial law fiasco.

The head of a task force established by Yoon's party to handle his eventual and “orderly” resignation, Lee Yang-soo, said the team would consider all options and timing for the president’s early departure “without any limitations”.

On Sunday, PPP leader Han Dong-hoon said the president would be excluded from foreign and other state affairs, and Prime Minister Han Duck-soo would manage government affairs.

That proposal has drawn criticism from the opposition, which says it is unconstitutional. It says Yoon must be impeached or resign and face legal prosecution, and plans to table another impeachment bill on Saturday.

Chang Young-soo, a professor at the School of Law at Korea University, said the president was able to delegate authority to the prime minister, especially his control of the military, but there is debate on whether the prime minister has the authority to act as head of state on diplomatic matters.

“Also, unlike a US vice president, a South Korean prime minister is not elected, which means democratic legitimacy is weak. So it will also be an issue how long this system can go on,” he said.

MILITARY BACKLASH

Opposition leader Lee Jae-myung said on Monday the political crisis threatened to cause irreversible harm to Asia's fourth-largest economy, a major global supplier of memory chips.

South Korea’s finance ministry and regulators said they would make all-out efforts to stabilise financial markets by deploying contingency plans and boosting liquidity by end-December.

In the latest sign of dissent within military ranks, the commander of South Korea’s special forces said he was ordered to send his troops into parliament last week to stop a vote to reject martial law.

Colonel Kim Hyun-tae, the commanding officer of the 707th Special Missions Group, said he took responsibility for his troops’ actions but he was acting under orders from then defence minister Kim Yong-hyun.

“We were all victims who were used by the former defence minister,” he told reporters outside the defence ministry.

He said he had not told the military about his plan to speak to the media out of fear he might be stopped.

Yoon’s decision to declare emergency rule stirred protests on the streets and raised alarm among Seoul’s allies.

US Defense Secretary Lloyd Austin scrapped plans to travel to South Korea and Secretary of State Antony Blinken called his South Korean counterpart, saying he expected the democratic process to prevail.

The United States has 28,500 troops stationed in South Korea, a legacy of the 1950-1953 Korean War.

The turmoil in Seoul comes at an important geopolitical moment in the region, with North Korea reportedly sending troops to help Russia’s war against Ukraine amid growing military ties between Moscow and Pyongyang.

South Korean foreign minister Cho Tae-yul told ministry officials: “We must also be unremitting in our efforts to restore the trust of our partners and once again measure up to the expectations of the international community towards Korea.”