Christchurch, Mar 17 (IANS): The man charged for Friday's twin mosque attacks in this New Zealand city is believed to have acted alone, police said on Sunday.

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

Police Commissioner Mike Bush confirmed that the 28-year-old was the only person charged with carrying out the shootings.

"He was stopped because he was believed to be a direct threat, our staff acted with absolute courage in intervening and had to use some force... they put themselves in harm's way to stop any further attack - and I do believe they did prevent further attacks," he said.

Three others arrested afterwards are not believed to have been involved, Bush said, but added that he could not be conclusive.

Police do not believe that two others arrested near the scene were involved. A woman was released without charge and a man was charged with firearms offences.

Fifty people were killed and 50 injured in what is New Zealand's worst attack. Two remain in a critical condition.

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.

He added that it was a sensitive process and that he was "aware of the cultural and religious needs".

On Saturday, the main suspect appeared in court 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.