Kim Yong-hyun, who resigned after the Dec. 3 martial law and is now jailed, testified before the nation's Constitutional Court, which is deciding whether to reinstate or fully remove Yoon from power after he was impeached on Dec. 14.

Central to Yoon's defence is that he never intended to impose military rule, using the decree only to break political deadlock.

"Yes," said Kim when asked by Yoon's lawyers whether the president had shot down the defence minister's recommendation to mobilise all military units stationed in Seoul, using around 7,000-8,000 troops to seize parliament.

Kim confirmed he had also proposed sending some units to the opposition party headquarters and a left-wing polling firm.

The Constitutional Court began its trial on Dec. 27 to review charges that Yoon violated his constitutional duty by imposing martial law without justification.

At an earlier hearing, the parliament's legal team presented testimony from military commanders and video footage showing military helicopters landing on parliament grounds with special forces troops breaking into the main building, as well as troops moving in on the National Election Commission.

An opposition Democratic Party lawmaker had condemned "the Dec. 3 insurrection," saying Yoon and supporters sought chaos by refusing to accept his recent arrest warrant.

On Thursday, South Korea's anti-corruption agency transferred its case to prosecutors, recommending they indict Yoon for insurrection and abuse of power.

In December Kwak Jong-geun, the commander of the Army Special Warfare Command, told a parliament committee that he received multiple telephone calls from Yoon as events unfolded, including an order to "drag out" lawmakers from parliament.

Kwak, who has since been indicted on insurrection charges, said he chose not to execute that order.

When asked about that report by a Constitutional Court justice on Tuesday, Yoon denied giving such a command.

TROOP DEPLOYMENTS

The testimony by Kwak differed from earlier statements by military officers that it was Kim who gave the order to extract lawmakers from parliament's chambers.

On Thursday, Kim conceded he had proposed declaring martial law to Yoon.

He said the president was concerned that the opposition party was obsessed with only three things - protecting the opposition leader from legal liabilities, impeaching government officials and launching special counsel investigations against Yoon.

He quoted Yoon as saying that the opposition's "parliamentary dictatorship and violence had gone out of control" and left no alternative.

About 1,605 soldiers and 3,144 police officers were deployed including to the National Assembly and the National Election Commission, according to indictments against army commanders reviewed by Reuters.

Some of those entered the parliament building itself, including by breaking windows, where they faced off with staffers who had used furniture to barricade doors and wielded fire extinguishers.

Yoon rescinded the martial law six hours later after parliament defied military and police cordons to vote against the decree.

During Thursday's hearing, Yoon disputed suggestions that the martial law had been thwarted, saying he always intended it to be a limited operation.

"This wasn't a failed martial law, it ended a little sooner than expected, as the National Assembly quickly demanded the lifting of it, and I also ordered the withdrawal of the military," Yoon said.

Kim said he shared names of people who might violate the decree with the defence counterintelligence commander on Dec. 3, but that it was not an arrest list.

Yoon could be seen occasionally nodding at Kim during the testimony.