The Australian terrorist who killed 49 people during Friday prayers at two mosques in New Zealand's Christchurch wrote in his "manifesto" that he supports U.S. President Donald Trump.
Entitled "The Great Replacement", the 73-page document said the gunman had wanted to attack Muslims.
41 of the victims were killed at Al Noor mosque on Deans Avenue and seven died at Linwood mosque.
The chief suspect, a 28-year-old Australian-born man, allegedly published a racist "manifesto" on social media before the attack, featuring conspiracy theories about Europeans being displaced, and details of two years of preparation and radicalization leading up to the shootings.
New Zealand Prime Minister Jacinda Ardern said the incident was a "terrorist act". One suspect in the slayings is reported by police to be in custody, but law enforcement has said they are still looking for other assailants and are treated it as an active shooter situation. Another victim died later in Christchurch hospital.
48 people with gunshot wounds were admitted to Christchurch Hospital.
In a 15-minute window, Reuters found five copies of the footage on YouTube uploaded under the search term "New Zealand" and tagged with categories including "education" and "people & blogs".
In addition to the footage - which AFP has verified, but is not distributing - a number of pictures were posted to a social media account showing a semi-automatic weapon covered in the names of historical figures, many of whomwere involved in the killing of Muslims.
One man who was there at the time said a man came in with an automatic rifle and was "just killing people".
New Zealand police described the footage shot by the gunman as "extremely distressing" and warned web users that they could be liable for up to 10 years in jail for sharing such "objectionable content".
Trump said on March 15 that he didn't see the manifesto himself.
Although some New Zealand residents have joined Islamist militant groups, the threat of terrorist attacks has consistently been regarded as low.
The gun laws in New Zealand are more layered and do not fit easily into a pro- or anti-gun rubric.
He saw about four people injured and two people lying on the ground.
The horrific death toll in the New Zealand mosque massacre has put the spotlight on the lethality of the semi-automatic weapons used by the Christchurch gunman and in numerous attacks in the United States.
Another witness said the man was wearing a helmet. The Bangladesh cricket team - which had been in Christchurch for a test match and was about to go into the mosque when the attack happened - all escaped without injury.
New Zealand's history of hunting, farming and sports shooting has led to a high rate of gun ownership.
"As family members with our New Zealand cousins today, we grieve, we are shocked, we are appalled, we are outraged, and we stand here and condemn absolutely the attack that occurred today by an extremist, right-wing, violent terrorist", Scott Morrison added.
In the United States, after the Sandy Hook and Parkland school shootings took place, as well as numerous other mass shootings in Las Vegas, Orlando, Sutherland Springs, Virginia Tech and elsewhere, we have really gained no new grounds in regulations that will help protect us from mass shootings in the future.
Only hours later, on Saturday morning, Ardern announced that New Zealand's gun laws would be changed, as she confirmed that the attacker held a firearms license.