A shooting at a mosque in Norway is being investigated as a possible act of terrorism, police say.

A gunman opened fire on the Al-Noor Islamic Centre, on the outskirts of the capital Oslo, on Saturday.

One person in the mosque managed to overpower the gunman and was injured in the process. The suspect was arrested after the attack.

Police also charged the suspect with murder after his 17-year-old stepsister was found dead in a separate location.

Acting chief of the police operation Rune Skjold said that the suspect, described as a white male, had been known to police before the incident but could not be described as someone with a "criminal background".

Mr Skjold said that the man appeared to hold "far-right" and "anti-immigrant" views and had expressed sympathy for Vidkun Quisling, the leader of Norway's collaborationist government during the Nazi occupation.

The suspect appears to have acted on his own.