SEOUL, March 20, 2025 (BSS/AFP) - South Korean opposition lawmakers called Thursday for extra security after an MP was hit in the face with an egg outside a court, with police bracing for unrest ahead of an expected ruling on the fate of the country's impeached president.

President Yoon Suk Yeol was suspended by lawmakers over his disastrous December 3 declaration of martial law, and the court last month held weeks of tense impeachment hearings to decide whether to formally strip him of office.

Despite experts predicting a verdict by mid-March, the Constitutional Court has yet to issue its final ruling -- making Yoon's case the longest deliberation in its history.

Opposition MP Back Hye-ryun was addressing reporters outside the court, urging justices to uphold Yoon's impeachment, when she was hit by at least one raw egg on Thursday.

Police later confirmed that bananas were also thrown.

Police have not identified an attacker. But authorities have pointed to Yoon supporters, who were staging a protest in the area.

"In light of the gravity of the case, we have formed an investigation task force," the Seoul Metropolitan Police Agency said in a statement.

Opposition lawmakers visited the National Police Agency, urging the police to reinforce security near the court.

Police plan to deploy "100 percent of available personnel" and are prepared to mobilise "all available equipment" on the day of the verdict to prevent clashes near the court, according to a police report seen by AFP on Thursday.

About 14,000 officers from 210 riot police units -- more than half of the entire national riot police force -- will be stationed in the capital Seoul.

"Plainclothes officers will be positioned inside the Constitutional Court, while police special forces will remain on standby in surrounding areas," the report stated.

Police have restricted access to 22 rooftops near the court and the area has been designated a "no-fly zone" with authorities preparing "anti-drone equipment".

The country's acting police chief has said previously the area around the court will be designated "a protest-free zone".

Police officers are also undergoing additional training involving the use of pepper spray and batons, with the force also considering deploying special units to "respond to bomb threats".

In addition to the impeachment verdict, Yoon also faces a criminal trial on charges of insurrection for declaring martial law in December, making him the first sitting South Korean president to stand trial in a criminal case.

He was detained in a dawn raid in January on insurrection grounds, but was released in early March on procedural grounds.

His supporters have been out protesting every weekend, with tens of thousands taking to the streets demanding the court reinstate him, with Yoon's release from detention appearing to invigorate his backers.