Seoul. South Korean investigators spent hours waiting outside the official residence of impeached President Yoon Suk Yeol as the presidential security service blocked them from executing a warrant to detain him, in the latest confrontation of a political crisis that has paralyzed South Korean politics and seen two heads of state impeached in under a month.

Yoon, a former prosecutor, has defied investigators' attempts to question him for weeks. The last time he is known to have left the residence was on Dec. 12, when he went to the nearby presidential office to make a televised statement to the nation, making a defiant statement that he will fight efforts to oust him.

Investigators from the country's anti-corruption agency are weighing charges of rebellion after Yoon, apparently frustrated that his policies were blocked by an opposition-dominated parliament, declared martial law on Dec. 3 and dispatched troops to surround the National Assembly.

Parliament overturned the declaration within hours in a unanimous vote and impeached Yoon on Dec. 14, accusing him of rebellion, while South Korean anti-corruption authorities and public prosecutors opened separate investigations into the events.

A Seoul court issued a warrant for Yoon’s detention on Tuesday, but enforcing it is complicated as long as he remains in his official residence.

Yoon's lawyers, who filed a challenge to the warrant on Thursday, say it cannot be enforced at his residence due to a law that protects locations potentially linked to military secrets from search without the consent of the person in charge. The warrant is valid for one week.

They've also argued that the Corruption Investigation Office for High-ranking Officials, which is leading a joint investigation with police and military investigators, lacks the authority to investigate rebellion charges. They said that police officers don't have the legal authority to assist in detaining Yoon, and could face arrest by either the “presidential security service or any citizens.” They didn’t elaborate further on the claim.

If investigators manage to detain Yoon, they will likely ask a court for permission to make a formal arrest. Otherwise, he will be released after 48 hours.

Thousands of police officers gathered at Yoon’s residence on Friday, forming a perimeter around a growing group of pro-Yoon protesters who braved subfreezing temperatures for hours, waving South Korean and American flags while chanting slogans in his support. There were no immediate reports of major clashes outside the residence.

Nearly five hours after dozens of investigators and police officers were seen entering the gate of the residence in Seoul to execute a warrant for Yoon’s detention, the dramatic scene appeared to have developed into a standoff. Two of Yoon’s lawyers, Yoon Kap-keun and Kim Hong-il, were seen entering the gate of the presidential residence around noon.

Seok Dong-hyeon, one of several lawyers on Yoon’s legal team, confirmed that the investigators arrived at the building but said it was unlikely that they would be able to detain the president on Friday. He said the agency’s efforts to detain Yoon were “reckless” and showed an “outrageous discard for law.”

The anti-corruption agency didn’t immediately reply to questions about whether investigators successfully entered Yoon’s residential building, but South Korea’s YTN television reported scuffles as investigators and police confronted the presidential security forces.

South Korea’s Defense Ministry confirmed that the investigators and police officers got past a military unit guarding the residence’s grounds before arriving at the building. The presidential security service, which controls the residence itself, refused to comment on whether its members were confronting investigators and whether they planned to block the detention attempt.

The liberal opposition Democratic Party called on the country’s acting leader, Deputy Prime Minister Choi Sang-mok, to order the presidential security service to stand down. Choi didn’t immediately comment on the situation.

“Do not drag the upright staff of the presidential security service and other public officials into the depths of crime,” said Jo Seung-lae, a Democratic lawmaker. Choi must “remember that swiftly addressing the rebellion and preventing further chaos is your responsibility,” Jo said.

Yoon’s defense minister, police chief and several top military commanders have already been arrested over their roles in the period of martial law.

Yoon’s presidential powers have been suspended since the National Assembly voted to impeach him on Dec. 14. Yoon’s fate now lies with the Constitutional Court, which has begun deliberations on whether to uphold the impeachment and formally remove Yoon from office or reinstate him. At least six justices on the nine-member Constitutional Court must vote in favor to remove him from office.

The National Assembly voted last week to impeach Prime Minister Han Duck-soo, who became acting president after Yoon’s powers were suspended, over his reluctance to fill three Constitutional Court vacancies ahead of the court’s review of Yoon’s case.

Facing growing pressure, the new acting president, Choi, appointed two new justices on Tuesday, which could increase the chances of the court upholding Yoon’s impeachment.