Around 8.30 pm, two men tried to raid Lidl supermarket on Sara Burgerthartstraat in West.
One of them threatened the staff present with a knife, but no loot was taken.
There is an ambulance on site, but police say the robbers injured no one.
The police are looking for the two men. The first robber is about 25 years old, 1.80 meters tall and has a thin stature. The man was wearing a black coat and a red cap, he has a shopping bag with him.
The second perpetrator is around twenty years old. He has a slightly medium skin tone and is also about six feet tall. He wears a jacket with white letters and a rip and dark trousers. He also wears a red cap just like the other man.
Anyone who sees the robbers is asked to call 112 and not to approach the man himself.