A lone gunman carrying multiple weapons was overpowered by members of the mosque before police arrived, witness says.

Norwegian police have said they are investigating a shooting at a mosque in the capital, Oslo, as a possible act of “terrorism”.

“We’re investigating this as an attempt at carrying out an act of terrorism,” assistant chief of police Rune Skjold told a news conference on Sunday.

A gunman armed with multiple weapons opened fire in a mosque near the Norwegian capital, Oslo, wounding one person before being overpowered by worshippers on Saturday afternoon.

Skjold said the suspect – a “young white man” had expressed support for Vidkun Quisling – a Norwegian politician who collaborated with occupying German forces during World War II – as well as anti-immigrant stances.

The man appeared to have acted alone, police said, and had been charged with attempted murder and murder for the time being.

The murder charge relates to the death of a young woman related to the suspect whose body was found in a home in the suburb of Baerum, where the shooting took place.

The Police were alerted to the shooting at the mosque shortly after 14:00 GMT.

They first reported that the victim had been shot, but later said one person had sustained “minor injuries” and that it was unclear if they were gunshot wounds.

The victim was a 75-year-old member of the congregation, mosque director Irfan Mushtaq told TV2.

Mushtaq said he had arrived at the scene shortly after being alerted about the gunman and had gone to the back of the building while waiting for police to arrive.

“The man carried two shotgun-like weapons and a pistol. He broke through a glass door and fired shots,” Mushtaq said, adding that the attacker wore body armour and a helmet.

He was overpowered by members of the mosque before police arrived, the mosque director said.

A Norwegian riot policeman stands in front of the al-Noor Islamic Centre mosque [AFP]

Increased security

Prime Minister Erna Solberg expressed her sympathy with those who were present at the mosque or were affected.

“It should be safe to go to the mosque, church or other worship places,” she said in a statement on Saturday, adding that it was too early to speculate over a possible motive.

She was joined by Abid Raja, a member of parliament for the Liberal Party who said there was a need to raise awareness against Islamophobia in Norway and welcomed messages of support from other Norwegians.

Police said they were assessing whether it would be necessary to step up security at mosques on Sunday, the start of the Muslim Eid al-Adha holiday.

The al-Noor Islamic Centre earlier this year implemented extra security measures following the massacre of more than 50 people at two New Zealand mosques by a self-declared white supremacist.

Norway was the scene of one of the worst-ever attacks by supporters of the far-right in July 2011, when 77 people were killed by Anders Behring Breivik.

Breivik said he was motivated by his hatred of multiculturalism, and detonated a massive bomb after which he opened fire on a gathering of the Labour Party’s youth wing on the island of Utoya.