Tunisian authorities have arrested four individuals accused of raising the Turkish flag, which closely resembles the Tunisian flag, atop a government building.

Footage circulated online in recent days showed the Turkish flag flying over the Tunis headquarters of the national railway company SNCFT, prompting a formal apology and arrests.

The two flags have the same colors and both bear the Islamic symbols of a star and crescent, with the most noticeable difference being a white circle on the Tunisian one.

SNCFT on Tuesday announced it had removed the wrong flag, apologizing in a statement for the mix-up and saying an investigation had been launched.

It said the Turkish flag had been purchased by mistake, and that the staff "didn't notice until it was raised."

The blunder did not go unnoticed on social media, and on Wednesday Mosaique FM radio and other Tunisian news outlets said four railway workers had been arrested.

The media reports did not elaborate on the identities of those arrested or the charges they may face.

In May, the covering of the national flag at a sporting event in Tunis, due to sanctions from the World Anti-Doping Agency, led to the arrests of three officials.

The sports officials faced charges including "attack on the flag of Tunisia" and "plot against the internal security" of the state, and were released last week after a three-month sentence.

The incident provoked outrage from Tunisian President Kais Saied, who has been readying for elections next month which he is widely expected to win.

Photos from the May flag incident showed Kais in tears during a visit to the venue.