Nobody received more than very minor injuries in the explosion on the second floor of an apartment building in the town of Norrköping at 6am on Wednesday, but two apartments were significantly damaged.
"There has been some kind of detonation. We can confirm that despite not yet having carried out the forensic examination of the scene," police spokesperson Thomas Agnevik told Swedish news agency TT early in the morning.
Police spent the morning scouring the scene for evidence and collecting witness statements.
According to unconfirmed reports in the Aftonbladet newspaper, the target was a senior member of motorcycle gang No Surrender. The organization was also the suspected target of several other attacks in the area in the past year – including one of the biggest explosions in Sweden in decades.
There were no immediate reports of connections to recent explosions in the Swedish capital which have been dominating headlines this week – one in the Husby suburb on Tuesday and another in the upmarket district Östermalm in central Stockholm on January 13th.
However, police said they were nevertheless continuing to look into possible connections with these and other blasts, as part of Operation Hoarfrost, an ongoing national task force investigating violent crime in Sweden.
Meanwhile on Wednesday, Stockholm police said one person was in custody in connection with the blast on Gyllenstiernsgatan in Östermalm last week.
"The investigation continues at full strength," read a police statement, which urged anyone with information to get in touch.
The explosion, which damaged windows and cars and could be heard several kilometres away, was described as "one of the most powerful explosions" in the capital. Nobody was injured in the blast.
