The cop shop in Malmo, Sweden, came under attack at 9.06pm local time (8.06pm GMT), Daily Star reports.
The explosion at the station in the Rosengard district of the city occured in an outside courtyard.
No officers or civilians are thought to have been injured but many vehicles have been damaged.
Sweden was last year rocked by terrorism when a lorry was driven into crowds on a busy Stockholm shopping street, killing five people.