South Korean President Yoon Suk-yeol was ousted by the Constitutional Court on Friday, which upheld parliament's impeachment motion over his imposition of martial law last year that sparked the country's worst political crisis in decades.

The ruling caps months of political turmoil that have overshadowed efforts to deal with the new administration of U.S. President Donald Trump at a time of slowing growth in Asia's fourth-largest economy.

With Yoon's ouster, a presidential election is required to take place within 60 days, according to the country's constitution.

Prime Minister Han Duck-soo will continue to serve as acting president until the new president is inaugurated.

"The Constitutional Court's unanimous ruling has removed a major source of uncertainty," Professor Leif-Eric Easley of Ewha University in Seoul told Reuters.

Acting Chief Justice Moon Hyung-bae said Yoon violated his duty as president with his December 3 martial law declaration, acting beyond the powers given to him under the constitution and describing his actions as "a serious challenge to democracy."

"(Yoon) committed a grave betrayal of the people's trust who are the sovereign members of the democratic republic," Moon said, adding that Yoon's declaration of martial law created chaos in all areas of society, the economy and foreign policy.

Thousands of people at a rally calling for Yoon's ouster, including hundreds who had camped out overnight, erupted into wild cheers on hearing the ruling, chanting "We won!"

Yoon is the second South Korean leader to be impeached by the court after Park Geun-hye in 2017. After weeks of tense hearings, judges spent more than a month deliberating the case, while public unrest swelled.

The decision shows "first and foremost the resilience of South Korean democracy," Son Byun-hwan, professor at George Mason University, told AFP.

"The very fact that the system did not collapse suggests that the Korean democracy can survive even the worst challenge against it – a coup attempt."

(With input from Reuters, AFP)

(Cover: People celebrate after President Yoon Suk Yeol's impeachment was accepted, near the Constitutional Court in Seoul, South Korea, April 4, 2025. /Reuters)