Volkswacht Bodensee - Clashes as S. Korean investigators attempt to arrest President Yoon

Yoon's 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 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.

Officials probing Yoon presented the warrant at his official residence, but were blocked from arresting him by his presidential guards, Yonhap reported.

"Investigators locked in standoff with presidential security service after showing search, detention warrants against Yoon," Yonhap reported.

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

TV footage showed investigators from the Corruption Investigation Office (CIO) that is probing Yoon and police officers trying to enter the residence's compound, but being blocked by unidentified personnel at the entrance gate.

Thousands of the embattled leader's die-hard supporters massed outside the presidential residence in the capital Seoul to protect Yoon, AFP reporters saw.

Yoon's lawyers were seen in front of the residence protesting the arrest warrant's execution.

A first attempt to arrest Yoon on January 3 failed after a tense hours-long standoff with his presidential guards, who refused to budge when investigators tried to execute their warrant.

A joint team of the CIO and police have since secured a new warrant and massed as many as 1,000 personnel for Wednesday's attempt to detain Yoon, according to local media reports.

They also threatened to detain anyone who obstructs the sitting leader's arrest after arriving at the residence on Wednesday, Yonhap reported.

Around 30 lawmakers from Yoon's ruling People Power Party also arrived at the residence to block investigators, the agency said.

Supporters of Yoon outside were heard chanting "illegal warrant!" while waving glow sticks and South Korean and American flags.

- Parallel trial -

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

There was heightened security around his compound in central Seoul with dozens of police buses and scores of uniformed police lining the street outside, AFP reporters saw.

Due to the tense situation, police decided not to carry firearms but only to wear bulletproof vests for the new attempt, 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 and his chief of staff on Tuesday made an appeal for the arrest efforts to stop.

Chung Jin-suk said his office was "ready to consider all options for investigation or visits" to the sitting leader "at a third location".

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 have blamed on purported safety concerns -- forced a procedural adjournment, the hearings will continue without Yoon, with the next set for Thursday.

Additional hearings are scheduled for January 21, January 23 and February 4.

F.Wagner--VB