Seoul, Dec 30 (IANS): South Korea's joint investigation team said on Monday that it has sought an arrest warrant for President Yoon Suk Yeol over his short-lived imposition of martial law, making him the first sitting President to face arrest.

The team said it sought the warrant on insurrection and abuse of power charges after Yoon ignored three summonses to appear for questioning.

The request was filed with the Seoul Western District Court at midnight on Sunday, according to the team comprised of the Corruption Investigation Office for High-ranking Officials (CIO), the police and the Defence ministry's investigation unit.

Investigators say Yoon led an insurrection and abused his power when he declared martial law on December 3 and allegedly ordered troops to the National Assembly to stop lawmakers from voting down the decree.

Yoon has denied the charges, saying his declaration of martial law was an 'act of governance' to warn the opposition party against what he described as its abuse of legislative power.

In response, Yun Gap-geun, one of Yoon's legal representatives, said they will submit a document of opinions to the court over the arrest warrant request and a notice of the appointment of lawyers later in the day, Yonhap news agency reported.

Yun earlier vowed to take 'formal steps' in response to the CIO's move.

"It's a request by an agency that does not have the authority to investigate (insurrection charges)," he told Yonhap News Agency, referring to the CIO.

Earlier on December 26, South Korea's anti-corruption investigation body summoned President Yoon Suk Yeol to appear for questioning over his brief imposition of martial law. The CIO for high-ranking officials issued the summons, ordering Yoon to appear at its office in Gwacheon, just south of Seoul.

This marked the CIO's third summons after Yoon ignored two previous summonses, including one for questioning on Christmas Day.

The CIO had teamed up with the police and the Defence ministry's investigation unit to look into allegations that Yoon had incited an insurrection and abused his power when he declared martial law on December 3.

Meanwhile, South Korean President Yoon's political future hung in the balance as the Constitutional Court deliberated on his impeachment trial over his short-lived martial law declaration, raising concerns about a leadership vacuum amid economic and security challenges.

Yoon faced an uphill legal battle after being impeached and subjected to widening probes into his failed attempt to impose military rule on the nation's democracy on December 3. The impeached President defended his imposition of martial law as an act of governance and denied charges of insurrection.