South Korea’s main opposition party on Wednesday urged President Yoon Suk Yeol to resign immediately or face impeachment, hours after Yoon ended short-lived martial law that prompted troops to encircle parliament before lawmakers voted to lift it.

On Tuesday night, Yoon abruptly imposed the emergency martial law, vowing to eliminate “anti-state” forces after he struggled to push forward his agenda in the opposition-dominated parliament. But his martial law was effective for only about six hours, as the National Assembly voted to overrule the president. The liberal opposition Democratic Party, which holds a majority in the 300-seat parliament, said Wednesday that its lawmakers decided to call on Yoon to quit immediately or they would take steps to impeach him.

Impeaching him would require support from two-thirds of the parliament, or 200 of its 300 members. The Democratic Party and other small opposition parties together have 192 seats. But when the parliament rejected Yoon’s martial law declaration in a 190-0 vote, about 10 lawmakers from Yoon’s ruling People Power Party cast ballots supporting the rejection, according to National Assembly officials. If Yoon is impeached, he’ll stripped of his constitutional powers until the Constitutional Court can rule on his fate. Prime Minister Han Duck-soo, the No. 2 position in the South Korean government, would take over his presidential responsibilities.