Prosecutors are seeking a 20-year prison sentence for a man who set fire to a Seoul subway train in May.

At the final hearing for the 67-year-old man, identified by his surname Won, at the Seoul Southern District Court on Tuesday, the prosecution requested the court to hand down a 20-year prison term, an order to wear an electronic tracking device for ten years and a three-year probation period.

The state said the defendant had threatened the safety of 160 innocent passengers by setting fire to a subway train that was passing through a tunnel under the Han River, motivated by grievances over the outcome of his divorce.

The prosecution asked for severe punishment citing the fact that Won's act had sparked fear and anxiety and that a delayed evacuation could have led to significant casualties.

The accused poured gasoline on, and set fire to, a Line Five subway train traveling between Yeouinaru and Mapo stations on May 31. 

Twenty-three passengers were subsequently hospitalized for smoke inhalation, 129 others received first aid at the scene and property damage totaled least 300 million won, or around 217-thousand U.S. dollars.

The court is set to make its ruling on October 14.