STOCKHOLM, Jan. 7 (Xinhua) -- Two people, were injured, one seriously, when an object exploded Sunday outside a subway station in southern Stockholm, the capital of Sweden.

The blast, at the Varby Gard station in the municipality of Huddinge, which is about 11 kilometers south of Stockholm, took place when someone picked up an object, which then exploded, Swedish Television reported on Sunday.

"Someone has used some kind of explosive. That's all we know," a local fire service chief told Swedish Television, which also reported that police and medics were at the location.

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.

Police told news agency TT that the two injured were a man in his 60s and a woman in her 40s. They were a couple and have been brought to hospital. The man is reportedly seriously injured. The woman's condition is unclear.

Sven-Erik Olsson of the Stockholm police 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.