An unidentified man walks on top of the Han River Bridge, April 17. Yonhap

A man was detained Wednesday after protesting on top of the steel arch of the Han River Bridge for five hours and causing a massive traffic jam during the morning rush hour as a section of the road across the bridge was closed for safety measures.

The man in his early 50s climbed up the arch and began a sit-in there at 5:40 a.m., hanging a banner under the name of the "Korean national salvation association," which called on the government and the ruling party to invoke the national emergency power.

Police and firefighter authorities deployed 67 personnel and 16 vehicles after receiving a report of the man at 5:52 a.m. They then installed an air mattress on the road and deployed a water rescue team in case of emergency.

The man came down five hours later using a crane that police deployed to bring him down.

Police took him into custody for questioning. (Yonhap)