South Korean authorities on Monday imposed an overseas travel ban on the country's President Yoon Suk Yeol as they carry out an investigation into his short-lived martial law decree.

A lawmaker asked during a parliamentary hearing whether Yoon had been banned from leaving the country. "Yes, that's right," said Bae Sang-up, an immigration services commissioner at the Ministry of Justice.

The head of South Korea's high-ranking official corruption investigation agency had earlier said that he had instructed investigators to seek a travel ban on Yoon.

Why is Yoon being banned from foreign travel?

Yoon declared martial law last week saying that he wanted to rid the country of "pro-North Korean forces," without providing details.

But the move plunged the country into political turmoil. 

Scenes of armed soldiers on the streets of the capital Seoul and surrounding the parliament shocked the nation. 

Amid massive political pressure, the president was forced to reverse the contentious decree within hours.

Yoon later apologized for his actions, but offered no resignation. 

Opposition parties vowed to impeach the embattled president but failed to do so over the weekend after most ruling party lawmakers boycotted a floor vote.

The People Power Party (PPP) claimed that it had blocked the motion to avoid "severe division and chaos." The party added that it would "resolve this crisis in a more orderly and responsible manner."

But the opposition vowed to submit a new impeachment motion against the president this week.

Can the president be detained?

On Monday, a senior National Police Agency officer said that, in addition to the overseas travel ban, police can also detain Yoon if conditions are met, the Associated Press news agency reported.

A sitting South Korean president generally has immunity from prosecution while in office.

But that does not extend to allegations of rebellion or treason.

This means that theoretically Yoon can be questioned and detained by police over his martial law decree. But many view it as unlikely as long as the president remains in office.

On Sunday, police arrested former Defense Minister Kim Yong-hyun for his alleged role in the attempt to impose martial law.

Kim was considered a key figure in the short-lived martial law decree. He had already resigned as defense minister.

sri/rm (AP, Reuters)