STOCKHOLM - A man has died after picking up what police believe was a hand grenade outside a subway station in southern Stockholm, the capital of Sweden, Swedish Television reported on Sunday.

A woman was also injured in the blast, at the Varby Gard station in the municipality of Huddinge, which is about 11 kilometers south of Stockholm.

"These two people cycled past the object and stopped to see what was on the ground. The woman who was with the man was several meters behind him," police officer Lars Alvarsjo told Swedish Television. "I don't dare imagine what would have happened if one or several children had found the hand grenade. This is totally unacceptable," Alvarsjo said.

According to Alvarsjo, hand grenades are increasingly used by criminal networks in Sweden. "It is surprising they have not detonated earlier," Alvarsjo said.

Police told news agency TT that the killed man, who was in his 60s, and the injured woman, who is in her 40s, were a couple. The report quoted police sources as saying that there was no indication that the explosion was directed against any individuals or property. The man and the woman simply "were at the wrong place and at the wrong time".

Police also said the man died at the hospital and that the woman was also taken to the hospital and had wounds on her face and both legs.

On Sunday morning, police searched the area around the station, which was cordoned off as a bomb squad was called in to carry out an investigation.

Sven-Erik Olsson of the Stockholm police at first told reporters that he could not say what kind of explosive material was used or how powerful the explosion was, only that it was "powerful enough for the couple to be taken to hospital".

The Varby Gard station was cleared on Sunday and the Stockholm subway was partially shut, with replacement buses serving part of the route on the affected line.

Police patrols will remain in the area throughout Sunday night and Monday, with the municipality offering crisis counseling to local residents. Police also called for witnesses to step forward with any information.

So far, police did not say whether the explosion was a terror-related incident.