Oslo police have made four arrests following a hand grenade explosion in Pilestredet on Tuesday evening. The incident, which occurred at approximately 8:15 PM, involved one grenade that detonated and another that failed to explode but was safely handled by authorities. No injuries were reported, though police emphasized the significant damage potential of the explosion.

Two 13-year-old boys were initially taken into custody on Tuesday night, with two additional older teenagers arrested on Wednesday evening. The older suspects are both above the criminal age of responsibility and have been charged with involvement in serious illegal handling of explosives. Police confirm that the two 13-year-olds remain in the care of child protection services and will be interviewed again on Thursday.

Investigators are working under the hypothesis that the explosion is connected to conflicts between criminal actors. Police Inspector Grete Lien Metlid stated that the leading theory suggests the teenagers may have taken on a "violence as a service" assignment, carrying out the attack on behalf of others. The target appears to have been a business premises near the explosion site rather than specific individuals.

The investigation continues to examine potential connections to a separate kidnapping case involving a 24-year-old man last week. Police are exploring whether there might be a motivational link, given that the kidnapping victim reportedly has family ties to the business owner operating from the premises near the explosion site. Authorities have not commented on possible international criminal connections and emphasize that further arrests remain possible as the investigation progresses.

Sweden's Stambanan through upper Norrland has reopened for traffic between Mellansel and Västeraspby, marking the restoration of the final damaged section following derailments caused by heavy rainfall in Västernorrland on November 6-7. The railway line resumed operations at approximately 1:30 PM on October 1, allowing train companies to begin running services along the route after weeks of disruption.

The repair effort faced significant challenges due to the extensive damage to both railway infrastructure and surrounding roads. Staffan Ökvist, Regional Maintenance Manager at Trafikverket, noted that the most difficult aspect was the scope of destruction, with multiple locations requiring simultaneous attention. Initial assessment proved difficult as damaged roads hampered access to the derailment sites, forcing crews to construct new access routes and work areas before restoration could begin.

Repair work involved substantial reconstruction efforts, including installation of new railway drums, rebuilding of the track bed, and repairs to both tracks and overhead power lines. Large quantities of earth materials and railway components were transported to the sites to facilitate the restoration. The railway authority also conducted track alignment runs using specialized trains to ensure the infrastructure met operational standards before reopening.

While the line is now operational, speed restrictions remain in effect on certain sections as work continues to stabilize the track bed. Trafikverket continues to prioritize rail transport management while monitoring the infrastructure's gradual return to full capacity. This restoration completes the recovery of Sweden's northern railway network, following earlier reopenings of the Botniabanan on September 15 and Ådalsbanan on September 24.