Volkswacht Bodensee - South Korea investigators attempt to arrest President Yoon

Investigators from the Corruption Investigation Office (CIO), which is probing Yoon's short-lived declaration of martial law, were let through heavy security barricades to enter the residence to attempt to execute their warrant to detain Yoon.

Yoon, who has already been suspended from duty by lawmakers, would become the first sitting president in South Korean history to be arrested.

Senior CIO prosecutor Lee Dae-hwan was seen entering the compound with other officials, according to AFP reporters.

Dozens of police buses and hundreds of uniformed police lined the street outside the compound in central Seoul, AFP reporters saw.

Some 2,700 police and 135 police buses have been deployed to the area to prevent clashes, the Yonhap news agency reported, after Yoon's supporters faced off with anti-Yoon demonstrators Thursday.

Yoon has been holed up inside the residence since a court approved the warrant to detain him earlier this week, vowing to "fight" authorities seeking to question him over his failed martial law bid.

The embattled leader issued the bungled declaration on December 3 that led to his impeachment and has left him facing arrest, imprisonment or, at worst, the death penalty.

It was unclear whether the Presidential Security Service, which still protects Yoon as the country's sitting head of state, would comply with investigators' warrants.

Members of his security team have previously blocked attempted police raids of his presidential residence.

- All-night prayers -

After staging chaotic protests Thursday, a handful of Yoon's die-hard supporters, which include far-right YouTube personalities and evangelical Christian preachers, had camped outside his compound all night -- some holding all-night prayer sessions.

"Illegal warrant is invalid" they chanted early Friday, as police and media gathered outside the residence.

"Yoon Suk Yeol, Yoon Suk Yeol," they yelled, waving red glow sticks.

Yoon's lawyer confirmed to AFP Thursday that the impeached leader remained inside the presidential compound.

Yoon's legal team has filed for an injunction to a constitutional court to block the warrant, calling the arrest order "an unlawful and invalid act", and also submitted an objection to the Seoul court that ordered it.

But the head of the CIO, Oh Dong-woon, has warned that anyone trying to block authorities from arresting Yoon could themselves face prosecution.

Along with the summons, a Seoul court issued a search warrant for his official residence and other locations, a CIO official told AFP.

South Korean officials have previously failed to execute similar arrest warrants for lawmakers -- in 2000 and 2004 -- due to party members and supporters blocking police for the seven-day period the warrants were valid.

F.Fehr--VB