There have been four explosions near a property owning company's offices and police are looking for more suspects.
The 15-year-old boy is held on suspicion of at least one of the detonations in Malmö's Rosengård area.
And police are also investigating a possible case of arson at Rosengård fire station. An office burned and there is smoke damage in the rest of the building, says an emergency spokesperson to news agency TT. He says a burglar alarm was set off just before the fire started.
This area suffers from high poverty; most residents are recent immigrants who often have an unemployment twice as high as the average. It also has seen several street riots over the years.