South Korea's President Yoon Suk-yeol on Tuesday declared emergency martial law, saying the measure was necessary to protect the country from "communist forces".

"To safeguard a liberal South Korea from the threats posed by North Korea's communist forces and to eliminate anti-state elements... I hereby declare emergency martial law," Yoon said in a live televised address to the nation.

He declared the step as critical for defending the country's constitutional order. It wasn't immediately clear how the steps would affect the country's governance and democracy.

Yoon since taking office in 2022 had struggled to push his agendas against an opposition-controlled parliament.

The president's conservative People Power Party had been locked in an impasse with the liberal opposition Democratic Party over next year’s budget bill. He has also been dismissing calls for independent investigations into scandals involving his wife and top officials, drawing quick, strong rebukes from his political rivals.

The Democratic Party reportedly called an emergency meeting of its lawmakers following Yoon's announcement. (Agencies)