The man charged over Friday’s twin mosque attacks in the New Zealand city of Christchurch is believed to have acted alone, police say.

Australian Brenton Tarrant, 28, a self-described white supremacist, live-streamed the attack on Facebook.

Three others arrested afterwards are not believed to have been involved, Police Commissioner Mike Bush said.

Tributes have been paid for the 50 victims while the first bodies are expected to be released for burial.

About 34 people are in hospital receiving treatment for injuries including severe gunshot wounds. A four-year-old girl remains in a critical condition.

Bodies to be returned by Wednesday

New Zealand Prime Minister Jacinda Ardern said her cabinet would discuss issues including gun policy reform on Monday, repeating that there would be “changes to our gun laws”.

Speaking to reporters on Sunday, she said parliament on Tuesday would pay tribute to victims of what she described as an “act of terror” and that she expected the bodies of all those killed to be returned to their families by Wednesday.

Ms Ardern also said there were “further questions to be answered” about the role of social media sites such as Facebook, which was used to broadcast live footage of the attacks. She said these platforms had “a wide reach” and this was “a problem that goes way beyond New Zealand”.

Facebook said it had removed as many as 1.5 million videos of the attack from its site in the first 24 hours and that “all edited versions of the video that do not show graphic content” were also being deleted.

Ms Ardern confirmed that her office had received a document from the suspect nine minutes before the attacks but that it did not contain any specific details, such as a location. She said it was forwarded to the security services within two minutes.

Separately, Commissioner Bush said authorities were working as fast as they could to finish formally identifying the victims of the attacks at the Al Noor and Linwood mosques. It was a sensitive process and that he was “aware of the cultural and religious needs”.

‘No-one else involved’

The main suspect appeared in court on Saturday in a white prison shirt and handcuffs, smiling for the cameras. He has been charged with one count of murder with more charges expected to follow.

Mr Tarrant had a firearms licence and owned five guns, Ms Ardern said. He did not have a criminal record and had not been on the radar of security services in New Zealand or Australia.