A man in Stockholm picked up a suspected hand grenade from the ground that detonated in his hand Sunday, accidentally killing him and injuring his female companion near a subway station, Swedish police said.

The blast took place about 11 a.m. just outside the Varby Gard subway station in Huddinge — a residential district in greater Stockholm, said regional police spokesman Sven-Erik Olsson.

Swedish police cordon off the area outside the Varby Gard subway station, where there was an explosion on Sunday. A man died and a woman was injured. (Henrik Montgomery/TT via AP)

"The man was seriously injured after he picked up something from the ground and this device exploded," Olsson said, adding that experts were examining the object.

The man, in his 60s, was rushed to hospital but later died while the woman, in her mid-40s, received "minor wounds" to her face and both legs, Olsson said.

Police said fragment damages on the victims and findings at the scene indicated the explosive could be a hand grenade, possibly an old one.

"We're suspecting that it's a hand grenade of some sort," Lars Alvarsjo, chief of Stockholm's southern police district, told the Swedish national broadcaster SVT.

Police initially were investigating the incident as an attempted murder, but later said there was no reason to believe that the couple was targeted. Olsson also said nothing has indicated that terrorism was involved.

Police checked in and around the subway station after the blast to make sure there were no additional explosive devices.

Alvarsjo said Swedish police have "unfortunately" noticed a rise in the use of hand grenades by criminal groups in the Nordic country. The three biggest cities in Sweden — Stockholm, Goteborg and Malmo — have seen several violent gang-related incidents in the past few years.

Many of the illegal hand grenades found in Sweden are being imported from former Yugoslav nations, he said.

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