In this combination photo, pro- and anti-impeachment rallies against and for President Yoon Suk Yeol take place across Seoul, the March 1 Independence Movement Day. Yonhap

Demonstrators both supporting and opposing impeached President Yoon Suk Yeol gathered for large-scale rallies in Seoul, Saturday, as the nation grapples with the political fallout from his failed martial law attempt and subsequent impeachment.

The rallies, coinciding with the anniversary of the March 1 Independence Movement against Japan's colonial rule, come after the Constitutional Court held its final hearing on Yoon's impeachment trial Tuesday, and began deliberations on whether to remove him from office or reinstate him.

Rallies led by conservative activist pastor Jeon Kwang-hoon and the conservative Christian group Save Korea began near the Gwanghwamun area in downtown Seoul and Yeouido in western Seoul at 1 p.m. to oppose Yoon's impeachment.

A total of 110,000 people had gathered for the two rallies as of 2:30 p.m., according to an initial police estimate, with people continuing to arrive.

Dozens of lawmakers from the ruling People Power Party attended the rally in Yeouido, including Rep. Yoon Sang-hyun, who delivered a message on behalf of the impeached president on the rally stage.

"When the will and the sense of responsibility to defend freedom are lost, communist totalitarianism and populism will take its place," the lawmaker quoted Yoon as saying. "We must fight until the end with that will and sense of responsibility."

At the rally, people carried signs that expressed opposition to Yoon's impeachment and support for his declaration of martial law, while others waved the Korean and U.S. flags, and chanted the impeached president's name.

Supporters of impeached President Yoon Suk Yeol gather for a rally in support of Yoon at Gwanghwamun Square in central Seoul, March 1. Yonhap

Meanwhile, a rally organized by the main opposition Democratic Party of Korea (DPK) and four other opposition parties took place just 1 kilometer away from the conservative rally in downtown Seoul at 3:30 p.m., calling for Yoon's removal from office.

DPK leader Rep. Lee Jae-myung was among the 13,000 people gathered for the rally near Anguk Station, according to a police estimate.

At 5 p.m., protestors were set to stage a march calling for Yoon's ouster in downtown Seoul. Around 100,000 people are expected to be present for the rally, according to the march organizations.

As tens of thousands gathered for the rallies, police have mobilized 6,400 officers and 230 police buses for crowd control.

About 5,000 officers will be stationed in the Gwanghwamun area, while the rest will be sent to maintain order in Yeouido.

Traffic has also been restricted on parts of Sejong-daero in downtown Seoul, as well as parts of Yeoui-daero in western Seoul.

Due to the large number of people gathered in downtown Seoul, subway trains temporarily passed Gwanghwamun Station without stopping, but normal operations resumed at about 3 p.m. (Yonhap)