Stockholm police destroyed a bag containing explosives that was found in a park in the Swedish capital late on Sunday night and are investigating further, they said on Monday.
The incident took place less than three weeks before a Sept. 11 general election in which crime is set to be a major issue among voters.
"Currently, there is no suspicion that this is a terror-related crime," daily Dagens Nyheter quoted Erik Akerlund, chief of police for the city's Norrmalm district, as saying.
A preliminary investigation has been opened and no one has so far been taken into custody. The police gave no details about who might have left the explosives or a possible target.
The park in central Stockholm where the explosives were found had been among venues for the city's annual Cultural Festival, which ran from Aug. 17 to Aug. 21, and had hosted concerts, family activities and events such as sumo wrestling.
The area was cordoned off and the bag disarmed by the bomb squad. Authorities carried out a forensic examination in the early hours of Monday morning, the police said.
"Now all the components will be examined," Akerlund said in a statement.
"It is only after a full examination at the national forensic centre that we will be able to say whether the dangerous object was functional."
Sweden's terrorist threat level has been at three on a scale of five - or "elevated" - since 2010 and security police said there had been no change as a result of the incident.
The country has not been at war for more than 200 years, but members of the armed forces have taken part in United Nations peacekeeping activities in Mali, Afghanistan, Iraq, Kosovo and other countries.
In 2017, an Uzbek asylum seeker killed five people when he drove a stolen truck into shoppers on a pedestrian street just a few hundred yards from Kungstradgarden. He said during his trial that he wanted to punish Sweden for its part in the global fight against the militant Islamic State group.
Police and security forces have foiled a number of other planned attacks.
In recent years, however, voters' attention has been focused on a surge in gang violence that has pushed Sweden to near the top of the table of shooting-related deaths in Europe relative to the size of its population.
Many polls put gang crime as the No.1 issue among voters ahead of the upcoming vote.
(Reporting by Niklas Pollard and Simon Johnson, additional reporting by Supantha Mukherjee; Editing by Catherine Evans and Bernadette Baum)
