The alleged gunman who launched a suspected terror attack on a mosque in Norway was inspired by the Christchurch, Poway and El Paso shooters, online records suggest.

The suspect has not been officially identified by police but was named in reports as Philip Manshaus, a 21-year-old local man.

Hours before the attack at the at the al-Noor Islamic Centre in Bærum in Saturday, a user of the same name posted on the Endchan messaging board.

“Well cobbers [friends] it’s my time, I was elected by [Christchurch mosque attacker] saint Tarrant after all,” it said. “We can’t let this go on.”

The post appeared to call for readers to enact their online posts about a race war “irl” – in real life – and said they had been personally “elected” for the task.

El Paso mass shooting: 20 killed at Walmart store Show all 39 1 /39 El Paso mass shooting: 20 killed at Walmart store El Paso mass shooting: 20 killed at Walmart store CCTV images of the gunman identified as Patrick Crusius The 21 year old, as he entered the Cielo Vista Walmart store in El Paso. The gunman was armed with an assault rifle and opened fire on shoppers at a packed Walmart store, killing 20. KTSM 9/AFP/Getty El Paso mass shooting: 20 killed at Walmart store Law enforcement agencies respond The Texas city’s police chief said the assault on a Walmart store on Saturday, which left another 26 people wounded, was being investigated as a potential hate crime. AFP/Getty El Paso mass shooting: 20 killed at Walmart store Shoppers exit with their hands up Shoppers exit with their hands up after a mass shooting at a Walmart in El Paso, Texas, U.S. August 3, 2019. REUTERS/Jorge Salgado NO RESALES. NO ARCHIVES. STRINGER Reuters El Paso mass shooting: 20 killed at Walmart store FBI released a picture of gunman Patrick Crusius The police officially identified the 21-year-old white male from Allen, Texas, a Dallas suburb some 650 miles east of El Paso. FBI/AP El Paso mass shooting: 20 killed at Walmart store A woman reacts after the mass shooting The attack came just minutes after a far-right manifesto appeared online. If authentic, it would make it the third mass shooting this year announced in advance on the website, which often features far-right and racist content. Reuters El Paso mass shooting: 20 killed at Walmart store Law enforcement responds to the active shooter The racist four-page document, titled “The Inconvenient Truth”, calls the Walmart attack “a response to the Hispanic invasion of Texas” and expresses support for the gunman who killed 51 people at two mosques in Christchurch, New Zealand earlier this year. AFP/Getty El Paso mass shooting: 20 killed at Walmart store A shopper hiding with an old lady behind the return and exchanges counter as the shooting began. Aaron Castaneda/Reuters El Paso mass shooting: 20 killed at Walmart store Ambulances in the car park near the scene It is ranked as the eighth-deadliest mass shooting in modern US history, after a 1984 shooting in San Ysidro, California, that claimed 21 lives. AP El Paso mass shooting: 20 killed at Walmart store Kendall Long (left) comforts Kianna Long (right) who was in the freezer section of Walmart. EPA El Paso mass shooting: 20 killed at Walmart store epa07755367 Police stand at attention after a shooting at a Walmart in El Paso, Texas, USA, 03 August 2019. According to reports, at least one person was killed and at least 18 people injured and transported to local hospitals. One suspect is in custody. EPA/IVAN PIERRE AGUIRRE IVAN PIERRE AGUIRRE EPA El Paso mass shooting: 20 killed at Walmart store Shoppers exit with their hands up. Reuters El Paso mass shooting: 20 killed at Walmart store Shopping carts sit next to a curb after the shooting. EPA El Paso mass shooting: 20 killed at Walmart store El Paso Fire Medical personnel arrive at the scene. AP El Paso mass shooting: 20 killed at Walmart store Walmart employees react after. AP El Paso mass shooting: 20 killed at Walmart store A woman runs to police near the scene. AP El Paso mass shooting: 20 killed at Walmart store Several law enforcement agencies respond. AP El Paso mass shooting: 20 killed at Walmart store People arrive at MacArthur Elementary looking for family and friends as the school is being used a re-unification centre. AP El Paso mass shooting: 20 killed at Walmart store Residents Erica Rios, 36, and Alma Rios, 61, cry outside a reunification centre. AFP/Getty El Paso mass shooting: 20 killed at Walmart store People gather in Juarez, Mexico, in a vigil for the Mexican nationals who were killed. AP El Paso mass shooting: 20 killed at Walmart store A child takes part in a vigil in Ciudad Juarez AFP/Getty El Paso mass shooting: 20 killed at Walmart store Francisco Castaneda joins mourners taking part in a vigil at El Paso High School. Reuters El Paso mass shooting: 20 killed at Walmart store Presidential candidate and former congressman Beto O'Rourke, right, meets with mass shooting survivor, Rosemary, at University Medical Centre Beto O'Rourke Facebook via AP El Paso mass shooting: 20 killed at Walmart store From left, Melody Stout, Hannah Payan, Aaliyah Alba, Sherie Gramlich and Laura Barrios comfort each other during a vigil for victims of the shooting. AP El Paso mass shooting: 20 killed at Walmart store A sign is posted near the scene Getty Images El Paso mass shooting: 20 killed at Walmart store Police cars parked below the Walmart sign block a road outside while investigating. EPA El Paso mass shooting: 20 killed at Walmart store Sherie Gramlich reacts during a vigil. AP El Paso mass shooting: 20 killed at Walmart store A man places flowers at the site Reuters El Paso mass shooting: 20 killed at Walmart store People take part in a rally against hate a day after a mass shooting at the Walmart store Reuters El Paso mass shooting: 20 killed at Walmart store Lupe Lopez holds a picture of a victim during a vigil for victims AP El Paso mass shooting: 20 killed at Walmart store People take part in a rally against hate a day after a mass shooting at a Walmart store, in El Paso, Texas, U.S. August 4, 2019. REUTERS/Jose Luis Gonzalez JOSE LUIS GONZALEZ REUTERS El Paso mass shooting: 20 killed at Walmart store Elsa Mendoza Marquez, a Mexican schoolteacher who was married and the mother of two adult children, was one of the victims Getty El Paso mass shooting: 20 killed at Walmart store People with the Mexican flag and the US flag take part in a rally against hate a day Reuters El Paso mass shooting: 20 killed at Walmart store People raise their arms in the air during a vigil for victims AP El Paso mass shooting: 20 killed at Walmart store People react and embrace each other Getty El Paso mass shooting: 20 killed at Walmart store Women light candles at a make shift memorial at the site of a mass shooting EPA El Paso mass shooting: 20 killed at Walmart store Adria Gonzalez (centre) who is being hailed as a hero for leading some Walmart customers to safety, speaks to the crowd AFP/Getty El Paso mass shooting: 20 killed at Walmart store People hold up their phones AFP/Getty Images El Paso mass shooting: 20 killed at Walmart store Beto O'Rourke speaks to the crowd AFP El Paso mass shooting: 20 killed at Walmart store People react during a prayer and candle vigil organized by the city, after a shooting left 20 people dead at the Cielo Vista Mall WalMart in El Paso, Texas, on August 4, 2019. - A shooting at a Walmart store in Texas left multiple people dead. At least one suspect was taken into custody after the shooting in the border city of El Paso, triggering fear and panic among weekend shoppers as well as widespread condemnation. It was the second fatal shooting in less than a week at a Walmart store in the US and comes after a mass shooting in California last weekend. (Photo by Mark RALSTON / AFP)MARK RALSTON/AFP/Getty Images MARK RALSTON AFP/Getty

It directed readers to a livestream on Facebook - which was used to broadcast the Christchurch attack - but said it did not work.

The Facebook page, which has been deleted, listed Oslo as Manshaus's hometown and displayed likes including a page called "NO to sex, YES to Jesus", which is thought to be satirical.

The Endchan post, which has also been removed, included a link to photos that appeared to show Manshaus through his childhood and more recently.

They appeared to match a photo of a Philip Manshaus who appeared aged 17 in a in a Norwegian news article dating from 2015, which detailed a literature campaign at the Oslo by Steinerskole school.

The post was signed off with: “It’s been fun, valhall venter [Valhalla awaits].”

It included a meme that described the Christchurch gunman, who massacred 51 Muslims at mosques in March, as a “saint” and praised his statements and manifesto.

It then described an American man who killed a Jewish woman at a synagogue in Poway, San Diego, as Tarrant’s “first disciple”.

The same image depicted the alleged El Paso shooter Patrick Crusius, who is accused of killing 22 victims in a terror attack targeting the Hispanic community, and praised him for “reclaiming his country”.

All three alleged shooters made last posts on the unmoderated messaging board 8chan, where they all shared “manifestos” seeking to inspire further white supremacist attacks.

8chan was shut down in the wake of the El Paso shooting on 3 August, amid heavy criticism of security services for allegedly overlooking the threat posed by the website and increasingly international character of far-right terrorism.

Photos of 'Philip Manshaus' were linked from a 4chan post made shortly before the shooting

Users have flocked to other websites and encrypted messaging services in its wake, and 4chan and Endchan initially remained online.

Both sites have their own “politically incorrect” /pol/ board, which was used by all four alleged shooters for their final posts.

Peter Neumann, founder of the International Centre for the Study of Radicalisation at King's College London, said that while removing extremists from mainstream platforms like Facebook and Twitter slashes their audience, “channers” find new homes.

“As predicted, taking down 8chan didn't have a long lasting effect, and people fairly quickly migrated to other platforms,” he told The Independent.

“Those forums are pretty niche to begin with, so it's not like they're exposing many innocent people to their stuff. They're more or less self-selected so I suspect the disruptive value is minimal.”

Writing on Twitter, Endchan's administrators said they took the image board offline temporarily in the wake of the shooting.

"It has been decided the site will stay up," they added on Sunday.

Witnesses said the Norway gunman was tackled to the ground by a 65-year-old worshipper who had been one of three men in the mosque.

The al-Noor Islamic Centre mosque in Sandvika, Norway on 11 August (REUTERS)

The attacker, who was reportedly wearing a uniform and body armour, broke through a glass door to reach the place of worship, where people were preparing to celebrate the Islamic festival of Eid al-Adha.

Police said several gunshots were fired and are investigating the shooting as a potential terror attack.

They have arrested a local white man in his 20s on suspicion of attempted murder.

The same man is also accused of killing his 17-year-old stepsister, whose body was found at her home.

“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 morning.

“We have uncovered extreme right-wing attitudes. The defendant has expressed opinions in which he praises [Norwegian fascist and Nazi collaborator] Quisling and is hostile towards immigration.”

Mr Skjold praised the “great courage” shown by two worshippers who tackled the gunman, adding: “There is no doubt that their efforts prevented this from having entirely different consequences.”

The suspect remains in custody and is undergoing a psychiatric assessment, officials said.