The two plain-clothes police officers were waiting in a traffic queue in their car at 2am on Saturday when they noticed shots being fired at a road sign near the corner of Amiralsgatan and Drottninggatan.
“One of the police officers stepped out of the car and identified himself. The other officer followed. As the second officer stepped out of the car they were shot at,” said police spokesman Sofie Österheim.
It is believed that the person who had shot the sign was the same person who shot at the police. The police officers returned fire at the gunmen. Österheim said she did not know how many shots the police fired.
On Saturday morning there was no information that anyone had been injured.
“We don’t know whether any of the assailants were injured. It’s not possible to establish,” said Österheim.
Police say they are looking for a silver BMW which was seen driving away from the scene.
“It is likely to have been shot in the windscreen and have a dent,” Österheim said.
Police are not revealing whether any guns have been recovered or giving details of the kind of guns that might have been used.
The scene of the crime has been sealed off and a forensic examination has started. The incident is being treated as a case of attempted murder.
The incident comes six weeks after a police officer was shot dead by a gunman in Nyköping, 100 km south of Stockholm.