The suspected shooter at the al-Noor Islamic Centre near the country’s capital was described as “a young white man” who appeared to have acted alone, police added.
The victim was a 75-year-old member of the congregation, mosque director Irfan Mushtaq told local station, TV2.
“The man carried two shotgun-like weapons and a pistol. He broke through a glass door and fired shots,” he said.
The shooter, who wore body armor and a helmet, was overpowered by members of the mosque before police arrived, Mushtaq added.
The mosque earlier this year implemented extra security measures following the massacre of more than 50 people at two New Zealand mosques by a suspected right-wing extremist.
In 2011, anti-Muslim neo-Nazi Anders Behring Breivik massacred 77 people in Norway’s worst peacetime atrocity, the majority of them teenagers at a youth camp.
(Production Credit Hywel Davies)