South Korean Constitutional Court upheld the impeachment of President Yoon Suk Yeol on Friday, removing him from office over his short-lived imposition of martial law in December.

The verdict, which was read by acting court chief Moon Hyung-bae and televised live, took effect immediately, requiring the country to hold a snap presidential election to pick Yoon's successor within 60 days, which many expect to fall on June 3, Yonhap news agency reported.

Yoon was impeached by the opposition-controlled National Assembly in mid-December on charges of violating the Constitution and laws by declaring martial law on Dec 3, deploying troops to the National Assembly to stop lawmakers from voting down the decree and ordering the arrest of politicians.

Yoon denied all charges.

According to CNN, Moon, the court’s acting head judge, said Yoon’s martial law decree was unconstitutional as there was no grave national crisis at the time and his reasons for declaring it “cannot be justified.”

The judge added that the president had violated the formal process of declaring martial law, infringed on lawmakers’ rights, and violated his duty as head of the armed forces by forcing soldiers to confront the public.

The report stated that the verdict was met with mixed reactions across the South Korean capital, with Yong’s opponents celebrating outside the court, “waving flags and dancing to music”.

However, the mood was more still and sombre outside Yoon’s official residence, where his conservative supporters had gathered.