The object must have been found outside a property on Amiralsgatan.
Föreningsgatan between Amiralsgatan and Kommendörsgatan has also been blocked off.
Traffic is redirected for the time being.
"At the moment we do not know what it is, but it is a smaller object," says Filip Annas, the police spokesperson.
The alarm came in at 09.48 from a private person.
- We work broadly, but the primary thing is to determine what something is and remove it from there, says Filip Annas, to TT.
National bomb protection is on its way to the site to investigate the object.