Yoon said on Tuesday night that opposition parties had taken the parliamentary process hostage. He vowed to eradicate “shameless pro-North Korean anti-state forces” and said he had no choice but to take the measure to safeguard constitutional order.

Yoon did not cite any specific threat from the nuclear-armed North, instead focusing on his domestic political opponents.

He complained of 22 impeachment motions filed against administration officials since he took office in May 2022.

The president’s approval ratings have hovered at near record lows amid a burgeoning influence-peddling scandal and clashes with the opposition-controlled parliament over budgets and investigations.

Shortly after Yoon made his announcement on live TV, people began gathering outside the parliament building, some of them shouting: “Withdraw emergency martial law!”

“Arrest Yoon Suk Yeol” shouted others.

The military had said activities by parliament and political parties would be banned, and that media and publishers would be under the control of the martial law command.

The decree also ordered striking doctors back to work. Those who violated martial law could be arrested without a warrant, it said.

The military named Army Chief of Staff General Park An-su, a four-star general, to head a martial law command and released the decree effective at 11 p.m. on Tuesday.

Masked martial law troops equipped with rifles, body armor and night-vision equipment had entered the National Assembly, where they faced off with staffers who opposed them with fire extinguishers.

As of early Wednesday there was no outward sign of government control of media outlets, which continued to report throughout the crisis.

South Korea has had a series of authoritarian leaders early in its history but has been considered democratic since the 1980s. It was the first time since 1980 that martial law has been declared in South Korea.

Yoon’s predecessor, Moon Jae-in of the Democratic Party, had said in a post on X that the country's democracy was in crisis. “I hope that the National Assembly will act quickly to protect our democracy from crumbling,” he wrote in a post.

“I ask the people to join forces to protect and save democracy and to help the National Assembly function normally.”

Washington is concerned by developments in South Korea, a White House spokesperson said, adding that the U.S. was in contact with the South Korean government and was monitoring the situation closely.

Some 28,500 U.S. troops are stationed in South Korea to guard against the North.

South Korea is an important trade partner for Poland, especially in terms of weapons systems. In 2022, Warsaw signed an agreement to purchase 1,000 K2 Black Panther tanks manufactured by South Korea’s Hyundai Rotem, along with an agreement to produce a Polish version of the tank, the K2PL, domestically.

As Poland ramps up defense spending after Russia’s invasion of Ukraine, Warsaw has also signed deals with Seoul for several dozen Chunmoo rocket artillery systems and FA-50 light combat jets.

Poland’s defense minister, Władysław Kosiniak-Kamysz, said in a message on X that the situation in South Korea would not affect Warsaw’s arms deals with Seoul.

He added: “We are monitoring the political situation in South Korea. We are in constant touch with our attaché in Seoul as well as his [South] Korean counterpart in Poland. We have received assurances from Deputy Defense Minister Il Sung speaking on behalf of the [South] Korean Defense Ministry, that our cooperation and the implementation of armament contracts is in no way jeopardized.”