The National Election Commission on Friday said the government dispatching soldiers to its offices Tuesday night was a clear violation of South Korea's Constitution and also of other laws, vowing legal action against those responsible.

"After the emergency martial law was declared on Dec. 3, about 300 martial law forces forced their way into the NEC headquarters and other offices. ... The troops confiscated the cellphones of five officials, blocked off the entrances and set a perimeter around the area, occupying the headquarters for 3 hours and 20 minutes," said Rho Tae-ak, the chairperson of the state-run election commission, after the agency's emergency meeting Friday morning at its headquarters in Gwacheon, Gyeonggi Province.

"Occupying the NEC, which is an independent organization under the Constitution, is a clear violation of the Constitution and of other related laws," Roh said, vowing to file legal charges against such actions.

Roh said none of the commission's data appears to have been taken out by the soldiers who entered the NEC offices, but officials are still checking to see potential damages caused by the troops' short occupation of the buildings.

President Yoon Suk Yeol at around 10:25 p.m. on Tuesday declared an emergency martial law, citing the need to protect the country from what he called "anti-state forces." He deployed troops to the NEC, the National Assembly, and moved to arrest his prominent political rivals, including main opposition Democratic Party of Korea leader Lee Jae-myung and ruling People Power Party leader Han Dong-hoon.

Despite the apparent attempt to block off the National Assembly, 190 of the 300 lawmakers gathered at the parliamentary building to pass a motion for the president to rescind the martial law, which Yoon did at around 4:30 a.m. Wednesday.

Surveillance footage shows military vehicles entering the NEC headquarters in Gwacheon at around midnight Tuesday. Hundreds of soldiers were also found to have occupied other NEC buildings across the greater Seoul area, including 47 deployed to its office in Gwanak-gu, southern Seoul.

The soldiers were at the NEC buildings until around 2:20 a.m. Wednesday, over an hour after the National Assembly passed an emergency motion to demand the president to rescind his declaration of martial law.

The military's incursion of the state election body, which is protected against outside intervention by the Constitution, is believed to be linked to allegations that the parliamentary elections in April of this year was manipulated.

Kim Yong-hyun, former minister of national defense who recommended Yoon to declare martial law, said that the raid on the NEC was for the military to acquire evidence on the election rigging allegations that had been raised by some members of the conservative bloc and conspiracy theorists on YouTube.

The main opposition party won 161 of the 300 seats in the National Assembly, while the ruling party managed to get only 108 seats, just barely enough to stop an impeachment vote of the president that requires approval from two-thirds of the lawmakers.

A monthslong police investigation of the election found no evidence to suggest election rigging. It was found that the Gwacheon Police Station, who investigated the accusation, decided not to forward the case to the prosecutors based on lack of evidence.