South Korean President Yoon Suk Yeol declared martial law in an unannounced late-night TV address Tuesday, accusing the country’s main opposition party of sympathizing with North Korea and of anti-state activities.

The last time a South Korean president declared martial law was in 1980, during a nationwide uprising led by students and labor unions.

In the surprise announcement, he cited a motion by the opposition Democratic Party, which has a majority in parliament, to impeach top prosecutors and reject a government budget proposal.

Soon after, South Korea lawmakers voted to block the martial law decree, with 190 of the 300 members of parliament voting to overturn the measure. It was not immediately clear what effect the vote will have but under South Korean law, the president is obliged to comply.

Yoon had labeled the opposition’s actions as “clear anti-state behavior aimed at inciting rebellion.” He further claimed these acts have “paralyzed state affairs and turned the National Assembly into a den of criminals.”

He described martial law as a necessary measure to eradicate these “shameless pro-North anti-state forces.” He justified the decision as essential to protect the freedoms and safety of the people, ensure the country’s sustainability, and pass on a stable nation to future generations.

The president assured the public, “We will eliminate the anti-state forces and restore the country to normalcy as quickly as possible.” While acknowledging that martial law might cause some inconvenience, he promised efforts to minimize its impact on the public.

While Yoon did not clarify what specific measures would be taken, Yonhap reported, citing the full military decree, which bans all political and parliamentary activities and allows arrests without a warrant.

The decree also prohibits “denying free democracy or attempting a subversion,” and outlaws “fake news” and “manipulating public opinion.” People who violate the decree can be arrested or raided without the need for a warrant, Yonhap added.

Citing the same document, Reuters reported that “strikes, work stoppages and rallies that incite social chaos” are also prohibited. That includes doctors who had been engaged in a walkout; they have been ordered by the decree to return to work within 48 hours.

Shortly after the president’s speech, members of South Korea’s parliament appeared to clash with authorities outside the National Assembly members’ building, as lawmakers scrambled to block the introduction of martial law.

Television footage showed troops attempting to enter the main hall of the National Assembly in Seoul.

Lee Jae-myung, the leader of the opposition Democratic Party, had previously ordered his lawmakers to the National Assembly.