The police's national unit working with protection against bombs, in Malmö, has advised people to be on the lookout for unexploded hand grenades which are believed to be spread throughout the southern city to some degree, reports news agency TT.

In just a short time, nine hand grenades have been used in Malmö, though not all of them have detonated.

The newspaper Sydsvenskan reports that if someone throws a hand grenade and it doesn't explode then, it can lie hidden under a car or in a bush, for example.

"There's a big risk that there are several, but that have not...