South Korean investigators attempted to arrest impeached President Yoon Suk Yeol on Wednesday over his failed martial law bid, using ladders to enter his residence compound after clashes broke out when his guards blocked the main gate.

Yoon has resisted arrest since a short-lived December 3 power grab plunged the country into its worst political crisis in decades, after he directed soldiers to storm parliament in an attempt to prevent lawmakers from voting down his move.

The former star prosecutor, who has already been suspended from duty by lawmakers, would become the first sitting president in South Korean history to be arrested if the court-ordered warrant is executed.

"The execution of the presidential arrest warrant has begun," acting President Choi Sang-mok said in a statement.

"This situation is a crucial moment for maintaining order and the rule of law in South Korea."

In a morning of high drama, a joint team of investigators from the Corruption Investigation Office (CIO) and police officers tried to enter the residence compound but were blocked by unidentified personnel at the entrance gate, AFP journalists observed.

Investigators were then involved in a "physical clash" as they tried to forcibly enter the residence, Yonhap reported, without specifying who they clashed with.

Punches were thrown as the rival sides pushed each other during the clashes between investigators and those defending the residence, an AFP journalist witnessed.

TV footage later showed around 20 personnel, believed to be investigators, climbing ladders into Yoon's residential compound.

AFP photos showed dozens of officers, marked with "police" and "CIO" on their backs, inside the compound. They were seen holding ladders and entering from at least two different entrances, an AFP journalist said.

Once inside, the officers bypassed a "second barricade" by going around buses parked to block the way, Yonhap reported.

At least one person was injured during the standoff and was transported away by fire authorities.

Yoon's lawyers were seen protesting the arrest warrant's execution in front of the residence. Later, a white police van attempted to enter the compound but was unsuccessful.

Choi, standing in for the suspended Yoon, said those responsible for "serious violations leading to unfortunate incidents" at the site would be punished.

A first attempt to arrest Yoon on January 3 failed after a tense, hours-long standoff with his Presidential Security Service (PSS), who refused to allow investigators to execute their warrant.

Supporters Removed

Investigators were also attempting to enter the residence via an alternative mountain hiking trail, according to Yonhap News TV.

The main road in front of Yoon's residence was completely blocked off with police bus barricades early Wednesday, while thousands of his die-hard supporters massed outside.

His supporters were heard chanting "illegal warrant!" while waving glow sticks and South Korean and American flags.

Police and CIO officers began forcibly removing the protesters from the entrance, while around 30 lawmakers from Yoon's ruling People Power Party obstructed investigators, Yonhap News TV reported.

Since the first failed bid, authorities have threatened to detain anyone who obstructs the sitting leader's arrest during the fresh attempt.

Police said they would execute an arrest warrant against the acting head of Yoon's presidential guards, Yonhap News TV reported Wednesday.

Parallel Trial

Yoon's guards have been seen in recent days installing barbed wire and barricades at the residence, turning it into what the opposition called a "fortress."

Due to the tense situation, police decided not to carry firearms but to wear bulletproof vests for Wednesday's new attempt, in case they encountered armed guards, local media reported.

If arrested, Yoon can be held for up to 48 hours under the existing warrant. Investigators would need to apply for another arrest warrant to extend his custody.

Yoon's legal team — who say he remains inside the residence — has decried the warrant as illegal.

In a parallel development, Yoon's impeachment trial began Tuesday with a brief hearing after he declined to attend.

Although his absence — which his team attributed to purported safety concerns — forced a procedural adjournment, the hearings will continue without him, with the next set for Thursday.