Clashes as S. Korean investigators attempt to arrest President Yoon

South Korean investigators tried 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 unsuccessful attempt to stop 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 carried out.

"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's compound but were blocked by unidentified personnel at the entrance gate, AFP journalists saw.

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

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

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

AFP photos showed scores of officers with "police" AND "CIO" marked on their backs inside Yoon's compound.

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

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

Yoon's lawyers were seen in front of the residence protesting the arrest warrant's execution, and later a white police van tried to enter the compound without success.

Choi, standing in for the suspended Yoon, said those who caused any unrest at the site would be punished.

"If there are serious violations leading to unfortunate incidents, I will hold them strictly accountable," he said.

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 budge when investigators tried 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 them from the entrance to the residence while around 30 lawmakers from Yoon's ruling People Power Party were blocking investigators, Yonhap News TV reported.

Since the first failed bid, authorities have threatened to detain anyone who obstructs the sitting leader's arrest in 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 only to wear bulletproof vests for the new attempt Wednesday, in case they were met by armed guards, local media reported.

If arrested, Yoon can be held for up to 48 hours on the existing warrant. Investigators would need to apply for another arrest warrant to keep him in custody.

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

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

Although his failure to attend -- which his team has blamed on purported safety concerns -- forced a procedural adjournment, the hearings will continue without Yoon, with the next set for Thursday.