Arizona Tribune - Yoon lawyer says to fight insurrection charge in court: Yonhap

Yoon, who has been stripped of his duties by parliament, is under investigation for his December 3 declaration, which plunged the country into political turmoil and led to a weekend impeachment vote.

Yoon's imposition of martial law "does not meet the requirements to constitute insurrection... (we) will contest it in court", said Seok Dong-hyeon of Yoon's legal team, according to Yonhap.

"While we do not consider the insurrection charges to be legally valid, we will comply with the investigation," he added.

The comments came hours after Yonhap reported investigators had notified Yoon he faced possible arrest if he did not appear by Saturday for questioning over his attempt to suspend civilian rule.

Yoon is being investigated by South Korean prosecutors as well as a joint team of police, defence ministry and anti-corruption investigators.

The president and some of his inner circle face possible life imprisonment, or even the death penalty, if found guilty. He remains under a travel ban.

An investigation unit earlier Tuesday launched a raid on Yoon's security service in an attempt to obtain phone records, the news agency said.

The same unit had previously asked that the suspended president appear to answer questions on Wednesday but were rebuffed by his office, an official told reporters.

Investigators requested Yoon appear at the office at 10 am (0100 GMT) for questioning on charges of insurrection and abuse of power, they said.

But the summons "was returned as 'undelivered'" by the presidential office, they said in a statement.

"The identity of the person who refused to accept it is unknown," they added.

- Turmoil -

South Korea's Constitutional Court, which began proceedings against Yoon on Monday, now has around six months to determine if it will uphold his impeachment.

A spokeswoman for the court said judges had pencilled in a preliminary hearing for December 27, which Yoon is not required to attend.

Fresh elections must be held within two months if his removal is upheld by the Constitutional Court. Prime Minister Han Duck-soo is serving as interim leader in Yoon's stead.

Vast protests against the ousted leader, with smaller rallies supporting him, have rocked the South Korean capital since his short-lived December 3 martial law decree.

Demonstrators in both camps have vowed to keep up the pressure as the Constitutional Court considers Yoon's fate.

On Monday night, hundreds of South Koreans held a vigil in central Seoul calling for his formal removal.

"I came here again, hoping that we will never have a president like this again," Kim Chan-suk, 67, told AFP at the rally.

"I am coming out every day to continue the fight until the Constitutional Court makes its ruling," protester Han Myung-hak, 52, told AFP.

O.Gutierrez--AT