SEOUL, July 09 (BSS/AFP) - South Korea's highest court is set to issue a verdict Thursday in a case against former president Yoon Suk Yeol over alleged crimes related to his failed martial law declaration and its chaotic aftermath.

The case covers accusations that Yoon had obstructed cabinet deliberations and used forged signatures of the prime minister in the lead-up to the 2024 declaration, as well as using presidential security agents to block his own arrest after lawmakers had nullified it.

The Supreme Court is due to announce its ruling at 2:00 pm (0500 GMT), following appeals against a lower court's decision.

The disgraced former president is already in detention while he appeals a separate life sentence for leading an insurrection with his martial law declaration, which he insists was motivated by the public interest.

The shock late-night national televised address in December 2024 that suspended civilian rule plunged South Korea into an unprecedented political crisis.

Martial law lasted only about six hours as lawmakers raced to vote it down in an emergency session.

However, Yoon's move triggered protests, sent the stock market plunging and caught key allies like the United States off-guard.

In the case brought before the Supreme Court, Yoon is accused of obstructing deliberations by convening only a select group of ministers for a meeting shortly before he declared martial law.

Other charges include allegedly creating and destroying a false martial law decree bearing forged signatures from the prime minister, ordering officials to distribute a misleading press release to foreign media, and directing an army commander to delete records from secure military phones.

In January, a lower court had sentenced Yoon to five years in prison after convicting him on most charges.

In April, an appeals court upheld the ruling, added a guilty verdict over the misleading press release, and raised the sentence to seven years.

Both prosecutors and Yoon's legal team had appealed to the Supreme Court, whose rulings are final.

The court said it would livestream Thursday's hearing after granting prosecutors' request.

In a separate case, a court handed Yoon a 30-year prison sentence for sending drones into North Korea to "manufacture" a crisis ahead of his martial law bid.

The former president has insisted his martial law declaration was "solely for the sake of the nation".

In 2024, he also defended it as necessary to root out "anti-state forces" and quash what he claimed were threats from North Korea.

Yoon was ousted over the martial law bid in April 2025, triggering elections that gave the presidency to Lee Jae Myung of the centre-left Democratic Party.

Several senior officials in Yoon's administration are also awaiting Supreme Court rulings in separate cases related to the martial law, including former prime minister Han Duck-soo and his interior minister Lee Sang-min.