LONDON -- South Korean President Yoon Suk Yeol declared an "emergency martial law" in a televised speech on Tuesday, the Yonhap news agency reported.

Yoon said the measure was necessary due to the actions of the country's opposition, which he accused of controlling parliament, sympathizing with North Korea and paralyzing the government.

This is a developing story. Please check back for updates.

ABC News' Joe Simonetti contributed to this report.