South Korean investigators arrest impeached President Yoon

South Korean authorities arrested impeached President Yoon Suk Yeol on Wednesday over insurrection allegations, with the embattled leader saying he agreed to comply with investigations to avoid "bloodshed", ending weeks of tense political standoff.

Since lawmakers voted to stand him down after his stunning, short-lived declaration of martial law on December 3, Yoon has been holed up at his hillside residence, guarded by a small army of personal security that blocked a previous arrest attempt.

His arrest, the first ever for an incumbent president, is the latest head-spinning development for one of Asia's most vibrant democracies even though the country has a history of prosecuting and imprisoning former leaders.

A defiant Yoon said he submitted himself for questioning to avoid any violence after more than 3,000 police officers marched on his residence to arrest him from the early hours on Wednesday.

"When I saw them break into the security area using firefighting equipment today, I decided to respond to the CIO's investigation - despite it being an illegal investigation - to prevent unsavoury bloodshed," Yoon said in a statement.

Yoon was seen arriving in his motorcade at the offices of the anti-corruption agency heading the probe on Wednesday morning.

Authorities now have 48 hours to question Yoon, after which they must seek a warrant to detain him for up to 20 days or release him.

Yoon's lawyers have argued attempts to detain Yoon are illegal and are designed to publicly humiliate him.

As local news broadcasters reported that Yoon's detention may come soon, some minor scuffles broke out between tearful pro-Yoon protesters and police near the residence, according to a Reuters witness at the scene.

Yoon's declaration of martial law stunned South Koreans, rattled Asia's fourth largest economy and ushered in an unprecedented period of political turmoil. Lawmakers voted to impeach him and remove him from duties on December 14.

Separately, the Constitutional Court is deliberating whether to uphold that impeachment and permanently remove him from office or restore his presidential powers.