Surroundings explosion

The police are searching for perpetrators after an explosion in a stairwell on Kungsholmen in Stockholm on Friday night.
The detonation occurred sometime after 2 am. The police have launched a hunt for the perpetrators, but by Friday morning, no one had been arrested.
No personal injuries have been reported.
"I can't say more than that we have launched a hunt for the perpetrator or perpetrators, and they are suspected of general endangerment and violating the law on fire hazardous and explosive materials, says Mats Eriksson, press spokesperson for the Stockholm police."

A lot of glass in the stairwell
The explosion occurred on the sixth floor of the apartment building, but it is still unclear what exploded.
"We don't believe it's a hand grenade, but it's unclear for now. No one has been injured, but there has been some property damage, mainly some glass in the stairwell, so we've asked people not to leave their apartments because of it, says Mats Eriksson."
At least one apartment door has been damaged in the explosion.
"There is also vandalism on the door, presumably to gain access to the stairwell."

Investigating potential target
A large area was cordoned off around the site, and the police are now trying to determine who or what the explosion may have been intended for.
"We're looking into what's behind this and we're trying to identify a potential target. But we'll see what connections there are to serious crime, says Mats Eriksson."
"There is no danger to the residents of the house or the area."