One person died and another was slightly hurt Sunday in a blast outside a metro station in a Stockholm suburb, police said.

A man in his 60s died after succumbing to injuries sustained when "according to witesses he picked up an object off the ground which promptly exploded," police spokesman Sven-Erik Olsson told AFP.

He died in hospital, police said on their website.

A woman aged 45 was also hurt, suffering facial injuries, police said.

The blast occurred mid-morning at the Varby gard station in Huddinge, a southern suburb of the Swedish capital.

Police cordoned off the station and the square where the blast happened as the bomb squad moved in to investigate.

The Expressen and Aftonbladet newspapers said the device was a hand grenade.

"It is too early to say. Technicians are still working on it. Nothing indicates that the (injured) couple were targeted," said Olsson, adding there was nothing to suggest an act of terrorism.