Ex-South Korean President jailed for life after declaring martial law

In this case, he also faced the death penalty.

Yoon, a staunch conservative, had defended his decree as necessary to stop liberals, whom he described as "anti-state" forces, from obstructing his agenda with their legislative majority.

The emergency rule triggered a national political crisis.

Prosecutors sought the death penalty in January, saying "his unconstitutional and illegal emergency martial law undermined the function of the National Assembly and the Election Commission, actually destroying the liberal democratic constitutional order."

The ruling lasted a mere six hours before being lifted after politicians managed to break through a blockade by hundreds of heavily-armed troops and police and unanimously voted to lift the measure.

The nation has not put a criminal to death since 1997 - a move widely seen as a de facto moratorium on capital punishment.

The court also convicted and sentenced several former military and police officials involved in enforcing the martial law decree.

Former defence minister Kim Yong Hyun received a 30-year jail term for his central role in planning the measure and mobilising the military.

Yoon was sentenced last month to five years in prison for resisting arrest, fabricating the proclamation and sidestepping a legally mandated full cabinet meeting before he declared martial law.

The Seoul Central Court has also convicted two of Yoon's cabinet members in other cases.

This included former prime minister Han Duck-soo, who received a 23-year prison sentence for attempting to legitimise the decree by forcing it through a cabinet council meeting, falsifying records and lying under oath, although he has appealed the verdict.

Among the defendants, two were found not guilty - Kim Yong-gun, the former chief of the defence ministry investigation bureau, and Yoon Seung-yeong, a former official at the police investigation bureau.

Yoon's lawyer said the verdict was "not backed by evidence," and accused the judge of following a pre-written script before delivering the sentence.

As he learned his fate, the former president reportedly "displayed no emotion".

Yoon was also found to have ordered the military to capture opposition leader and now president - Lee Jae Myung, the court ruled.

Other verdicts included Yoon being found guilty of abuse of authority and committing acts to subvert constitutional order.

However, the court found there was insufficient evidence that Yoon had planned the imposition of martial law a year in advance, as argued by prosecutors.

Pro-Yoon supporters gathered outside the court to show support for the former president, fearfully awaiting the verdict of the trial.

After the sentence, one "angry" supporter took to the stage and started "attacking" a cameraman for local channel KBS with his flag, according to reports, with much anger directed at media representatives.