South Korea's acting president urges calm, tighter security ahead of impeachment ruling

South Korea's interim leader called on the nation on Wednesday to calmly accept the decision from the Constitutional Court on the impeachment of President Yoon Suk Yeol, as police ramped up security around the court ahead of the ruling on April 4.

At a ministerial meeting on safety ahead of the ruling, acting President Han Duck-soo said he "strongly asked" politicians not to make any comments that could incite violence.

"The government will not tolerate any illegal or violent acts. No matter what decision is made, we must accept the results calmly based on the rule of law," Han said.

"If we can become one again with your strength and wisdom, we can overcome this crisis of confusion and conflicts," he said.

The Constitutional Court, which is reviewing Yoon's impeachment over the shock martial law order, said it will announce its decision on whether to remove him from office permanently or reinstate him on Friday, April 4.

Yoon was impeached by parliament on December 14 after being accused of violating his constitutional duty by declaring martial law in early December with no justifiable grounds.

If the court rules to oust him, a new presidential election must be held within 60 days.

South Korean police have beefed up security in areas around the court, preparing to deploy all forces from midnight into the ruling day on Friday.

The acting chief for the national police force, Lee Ho-young, said the area around the court would be turned into a "vacuum state" to restrict access and cordon off pro-and anti-Yoon rallies to prevent any potential clashes.

Vowing to act sternly against any violence, Lee said police will arrest those who vandalise facilities, threaten justices or assault police officers.

In January, hundreds of Yoon supporters stormed a court building after his detention was extended, smashing windows and breaking inside.

Han has directed police to step up security for constitutional court justices.

Bracing for big rallies and a heavy police presence on the ruling day, foreign embassies have issued alerts calling for extra caution.

The US embassy in Seoul said on Wednesday that it would cancel routine consular operations like visa interviews on the afternoon of April 3 and all day on April 4. The Chinese embassy has told its nationals to stay away from large political protests and not to participate in those rallies.