Police have surrounded the branch and blocked off the square near the bank. The robbers are still barricaded inside the bank and holding the bank employees hostage.
It is not yet clear whether there were also customers at the time of the incident. A dozen police cars have arrived outside and set up a security area to avoid risks to passers-by.
According to some media reports, the robbers took some safe deposit boxes and escaped through a hole in the wall.
A massive manhunt was unleashed by the police.
Ambulances were also sent to the scene as a precaution.