An overnight shooting in the Norwegian capital, Oslo, that killed two people and wounded more than a dozen is being investigated as a possible terrorist attack, Norwegian police said on Saturday.

In a news conference on Saturday, police officials said the man arrested after the shooting was a Norwegian citizen of Iranian origin who was previously known to police but not for major crimes.

They said they had seized two firearms in connection with the attack: a handgun and an automatic weapon.

READ MORE: 'Forced motherhood is illegitimate'

The events occurred outside the London Pub, a bar popular with the city's LGBTQ community, hours before Oslo's Pride parade was due to take place.

Organisers canceled all Pride events planned for Saturday on the advice of police.

"Oslo Pride therefore urges everyone who planned to participate or watch the parade to not show up. All events in connection with Oslo Prides are canceled," organisers said on the official Facebook page of the event.

Police spokesman Tore Barstad said 14 people were receiving medical treatment, eight of whom have been hospitalised.

Olav Roenneberg, a journalist from Norwegian public broadcaster NRK, said he witnessed the shooting.

READ MORE: Ukraine retreats from city after long fighting, handing Russia a win

"I saw a man arrive at the site with a bag. He picked up a weapon and started shooting," Roenneberg told NRK.

"First I thought it was an air gun. Then the glass of the bar next door was shattered and I understood I had to run for cover."

Prime Minister Jonas Gahr Stoere said in a Facebook post that "the shooting outside London Pub in Oslo tonight was a cruel and deeply shocking attack on innocent people."

He said that while the motive was unclear, the shooting had caused fear and grief in the LGBTQ community.

"We all stand by you," Gahr Stoere wrote.

Christian Bredeli, who was at the bar, told Norwegian newspaper VG that he hid on the fourth floor with a group of about 10 people until he was told it was safe to come out.

READ MORE: Protests sweep US after abortion rights overturned

"Many were fearing for their lives," he said.

"On our way out we saw several injured people, so we understood that something serious had happened."

Norwegian broadcaster TV2 showed footage of people running down Oslo streets in panic as shots rang out in the background.

Norway is a relatively safe country but has experienced violent attacks by right-wing extremists, including one of the worst mass shootings in Europe in 2011, when a gunman killed 69 people on the island of Utoya after setting off a bomb in Oslo that left eight dead.

In 2019, another right-wing extremist killed his stepsister and then opened fire in a mosque but was overpowered before anyone there was injured.

Australian researchers have made a world-first breakthrough into the study of migraines, linking genetics and brain size to the severity of the chronic condition.

It's hoped the research could fast track the development of more effective treatment for millions of migraine sufferers around the world.

Nine.com.au National Chief of Staff Freya Noble said migraines have caused her excruciating pain for the last 10 years.

READ MORE: Protests sweep US after abortion rights overturned

"I start to lose my vision, I get numbness in my face, I'll start to feel dizzy and then I've got about half an hour before I'm totally incapacitated in bed," she said.

"It can be really, really hard at times… There's been a lot of missed work, missed events.

"And it's really expensive to be sick as well."

Noble said she's tried multiple medications and solutions in a bid to find relief with varying degrees of success.

"It's a lot of trial and error, you feel like a bit of a science experiment," she said.

Migraines are considered a neurological disorder which affect one in four, or almost five million Australians, impacting more women than men.

Migraines present as severe and debilitating headaches – usually on one side of the head – that cause a painful throbbing and pulsing feeling, often accompanied by nausea, dizziness, vomiting and sensitivity to light and sounds.

Over half of all people who suffer from migraines do not respond to treatment at all.

The condition can last a few hours or even weeks and months, with productivity loss and health care expenses costing the nation's economy an estimated $35.7 billion a year.

Dr Brittany Mitchell is the lead scientist behind the new research, facilitated by the QIMR Berghofer research institute in Brisbane.

She said those with smaller brains and smaller brain structures are more likely to experience migraines.

"We found for the first time brain size might actually influence the risk of having migraines," Dr Mitchell said.

READ MORE: 'This is not over': Biden vows to fight for abortion rights

"Our research found that a smaller brain size and smaller structures within the brain, such as the hippocampus and the amygdala, cause an increased risk of migraine, and that this might be due to shared biological pathways that affect neuronal signalling or the regulation of blood flow."

The study examined hundreds of thousands of patients to make the world-first discovery.

Dr Mitchell said it's an exciting step towards furthering knowledge of the complex condition and developing more effective treatments.

"As a migraine sufferer myself I know how debilitating this can be," she said.

"This gives us very exciting opportunities to look at possible avenues where we can target new treatments."

Originally published on Te Ao Māori News The office of Kīngi Tuheitia has taken the unusual step of issuing a media statement to voice its disapproval of the marriage of the King’s son, Whatumoana Paki.Whatumoana,…

The search for a missing swimmer at a South Island waterfall has finished for the day, and efforts are likely to be scaled back tomorrow. The swimmer has been missing since about midday yesterday after one other person was pulled…

National are the sole main New Zealand political party not to publicly denounce the US Supreme Court’s decision to overturn a landmark abortion rights ruling.The decision to overturn the 1973 Roe v Wade ruling, which gave women…

Angry Jetstar passengers can be heard arguing with staff in a video after the airline yesterday cancelled an Auckland to Melbourne flight at the last minute.Pooja Pankaj Anand, her husband and their three-year-old were among those…

Two people who were on one motorcycle have been taken to hospital with serious injuries following a crash in Tuakau this afternoon. A police spokeswoman confirmed emergency services were alerted to the incident on Buckland Rd just…

A woman has died after a “potential stabbing” on a Christchurch street with police taking two men into custody following the incident.Ambulance teams earlier found the woman on Cheyenne St in the suburb of Sockburn at about 4.20pm.”On…

An amateur boxer who moved from New Zealand to Australia when he was a minor is set to be deported after two street fights that left people hospitalised, followed by an incident during Queensland’s first Covid-19 lockdown in which…

Test your brains with the Herald’s afternoon quiz. Be sure to check back on nzherald.co.nz for the morning quiz tomorrow. To challenge yourself with more quizzes, CLICK HERE.