Yoon’s declaration caught many off guard – it’s a fast-moving situation now.
The political opposition has called on the public to gather in protest outside parliament – peaceful mass demonstrations are common in South Korea and they have proven effective in changing governments before.
The main opposition Democratic Party on Tuesday night immediately called for all its lawmakers to assemble at the National Assembly.
Under South Korean law, the government must lift martial law if a majority in parliament – the National Assembly – demands it in a vote. The same law also prohibits martial law command from arresting lawmakers.
But police buses had already been moved into place in front of the building in what is being viewed as a barricade to stop lawmakers from reaching the assembly.
There is also discord within Yoon’s own party, the People’s Power Party leader.
Its leader Han Dong-hoon has called the declaration of martial law a “wrong” move, South Korean outlet Yonhap is reporting. He has vowed to block the law.