People calling for President Yoon Suk Yeol's impeachment hold a rally in front of Gyeongbok Palace in Seoul, Dec. 28. Yonhap

Tens of thousands of people gathered in downtown Seoul, Saturday, to rally for or against the impeachment of President Yoon Suk Yeol in the wake of his short-lived imposition of martial law.

Police estimated 35,000 people took part in anti-Yoon rallies near Gyeongbok Palace as of 5:10 p.m., though organizers put the number at over 500,000.

K-pop music blared through loudspeakers as protesters dressed in thick winter gear waved light sticks and chanted, "Immediately arrest Yoon Suk Yeol."

Some called on the Constitutional Court to remove him from office while others demanded the dissolution of Yoon's ruling People Power Party (PPP).

Lee Jae-myung, the leader of the main opposition Democratic Party, was reported to have visited the site.

People supporting President Yoon Suk Yeol hold a rally near Gwanghwamun Station in Seoul, Dec. 28. Yonhap

Just 1 kilometer away, near Gwanghwamun Station, Yoon's supporters held their own rally.

"Impeachment is invalid," read a sign held up by a protester. "Arrest Lee Jae-myung," another read.

PPP Rep. Yoon Sang-hyun made an appearance and addressed the supporters from a stage.

"We failed to stop the impeachment motion against our own party's president. I apologize to our honorable patriot citizens," he said before bowing on his knees.

Police said around 35,000 people were gathered at the rally as of 5:10 p.m., while organizers claimed the number was close to 3 million. (Yonhap)