STOCKHOLM (Reuters) - Two people were killed and two injured in a shooting at a restaurant in eastern Sweden late on Thursday that police said appeared to be part of an escalating spiral of violence among criminal gangs.

Sweden has been rocked by a wave of shootings and bombings in recent years that has intensified over the past months to become an almost daily occurrence.

Police on their website said several people were taken to hospital following the shooting at a restaurant in the small town of Sandviken 190 kilometres north of Stockholm, and that two had died from their injuries.

"We are investigating the connections to the shootings we have had in the past in Sandviken and also to the recent spiral of violence," police spokesperson Magnus Jansson Klarin told Swedish news agency TT.

"It probably has links to the criminal environment, but I can't say which grouping it would be about," he said.

Jansson Klarin said police suspected one of the dead was the target of the attack, while the other three struck were likely random unintended victims.

(Reporting by Anna Ringstrom; Editing by Peter Graff)