Bulgarian police closed off for about 35 minutes Wednesday the Vassil Levski Stadium metro station in Sofia over a suspicious box.

The incident happened at around 6 pm as the box was discovered to be unattended. This led the police to seal one of the busiest metro stations in Sofia for passengers. Subway trains continued traveling through the station without stopping there for the duration of the alert.

Upon inspection, it turned out that the suspicious object was an empty shoe box. In the words, of the Director of the Sofia Metropolitan company, Stoyan Bratoev, the box was most likely left behind at the Vasil Levski station by a person who changed his old shoes with a newly-bought pair, and then got on some of the subway trains.

The Sofia Metro continued to function normally after the alert was lifted.