One person has been taken into custody after he opened fire inside a mosque in the Norwegian capital Oslo.
"One person is shot. The severity of that person's injuries is unknown. One suspect is arrested. The police are working at the location," Oslo police said on Twitter.
Later a woman was found dead at the house of the suspect.
"A young woman was found dead at the suspect's address," assistant chief of police Rune Skjold told the media, adding that the man was suspected of murder.
According to reports, the gunman was dressed in black and wore a helmet and bulletproof vest.

North Korea fires short-range ballistic missile, South Korea says
Wildfire prompts evacuation alert in metro Vancouver
Israel strikes south Lebanon after soldiers killed, talks continue in Rome
Italy on red alert, Hungary turns off the lights as Europe's heatwave takes tollĀ
Russian strikes kill six in Ukraine's Balakliia, Sumy, officials say