According to witness accounts, most of the evidence indicates that it was thrown in, says police spokesman Robert Sennerdal.
"Nothing has exploded," he continues.
There were guests at the restaurant, but everyone got out and no one was injured.
The alarm about the suspicious object came shortly after 9 p.m.
We have initiated a preliminary investigation into attempted public destruction in order to be able to take investigative measures.
National bomb disposal technicians have been called to the scene.
