HELSINKI (AP) — Swedish police say they have detained three people in connection with an explosion in an apartment building in the southern city of Malmo.

No-one was injured in the blast, which broke the building’s main door, blew out windows and substantially damaged the entrance level in a southern district of Sweden’s third largest city early Saturday.

Police spokesman Peter Martin told Swedish news agency TT that initial information suggests the explosion has no connection to a blast early Friday in another Malmo district where a parked car and a nearby building were damaged.

Later Saturday, a police bomb squad was alerted to a central Malmo park to examine an unidentified suspicious object. TT said the national bomb squad has been called out to examine suspected bombs nationwide 30 times in the past two months and 100 times this year.