A man in Incheon inscribed SOS on a piece of cardboard, right, and hung it outside a window asking for help after being locked inside an apartment building. Screen captured from National Police Agency's Facebook account

A man in Incheon was rescued after being trapped in a small space within his apartment flat for 20 hours. The successful rescue was attributed to the man's resourcefulness and a neighbor's response, according to police on Monday.

On the last day of 2023, the man in his 70s found himself locked inside the building's evacuation area, which is a mandatory 6.6 square meter space in new apartment buildings designed for fire emergencies. Stranded without a phone in the cold for 20 hours, he resorted to desperate and resourceful measures.

He discovered a piece of cardboard and a knife and used the blade to inscribe "SOS" on the paper. He then suspended the message outside his window, hoping that someone would notice and alert the police.

His hopes were realized when a resident in a neighboring apartment building spotted the message and promptly called the police.

"The message was small and could have been gone unnoticed," said a police officer who was dispatched to rescue him, according to Yonhap News Agency.

Upon reaching the apartment building, the police systematically checked each home from the 15th floor upward. Identifying an unresponsive home, the police looked up its owner and was able to call his son, who swiftly arrived at the scene and unlocked the apartment.

Upon being rescued, the man, visibly shivering from the freezing cold, revealed that he had entered the evacuation space to open the windows when he became trapped.

Expressing gratitude, the man extended his thanks to his neighbor for alerting the police.

"At first, I thought it was a prank," a police officer said. "Thanks to that young man, we were able to save the guy."

The rescue story gained public attention this week after the National Police Agency shared a post about it on its Facebook account.