South Korean President Yoon Suk-yeol has been named by police and prosecutors as a suspect in investigations into charges of treason, rebellion and abuse of power against the president and several senior government and military officials involved in martial law operations last week, according to Yonhap.

"Securing necessary documents is paramount. We are making the decision based on a comprehensive assessment, including the possibility of him leaving the country," a South Korean police officer said at a press conference when asked why Mr. Yoon was not banned from traveling, according to Yonhap.

Asked about the possibility of arresting Mr. Yoon without a warrant, the official, who did not reveal his identity, replied that it could be done if the requirements were met.

South Korean police have also not ruled out the possibility of directly questioning President Yoon, according to Yonhap. "There are no restrictions on who is being investigated," Woo Jong-soo, a senior South Korean police official, told reporters.

Police have set up a special team of about 150 investigators to handle the case.

President Yoon declared martial law on December 3 but lifted it just hours after parliament convened despite a blockade by security forces to prevent voting.

South Korea's 707th Special Forces Commander Kim Hyun-tae told reporters today that he had received orders to bar lawmakers from entering the chamber to prevent a vote to lift martial law.

Kim Hyun-tae added that his unit entered the parliament grounds with orders to block the main building to prevent lawmakers from entering but was blocked by lawmakers inside. "We are all victims of former Defense Minister Kim Yong-hyun's abuse," Kim Hyun-tae told reporters outside the Defense Ministry in Seoul.

Mr Kim Hyun-tae stressed that he took full responsibility for the soldiers' raid on the parliament but insisted he acted on orders from the defence minister. "The members of the group are innocent. Their only crime was that they followed the orders of their commander," Mr Kim Hyun-tae said, fighting back tears.

Former South Korean Defense Minister Kim Yong-hyun was arrested on December 8 for his role in declaring martial law and ordering troops to be deployed to parliament.

Meanwhile, President Yoon escaped an impeachment vote in parliament on December 7 that plunged South Korea into a constitutional crisis.

President Yoon said before the vote that he had entrusted his fate to the ruling party, but he did not offer to resign.

A spokesman for the South Korean Defense Ministry said today that President Yoon remains the commander-in-chief of South Korea, according to Reuters.