A New Zealand judge sentenced mosque gunman Brenton Tarrant to life in prison without parole Thursday for the massacre of 51 Muslim worshippers, saying his crimes were "wicked" and "inhuman". Judge Cameron Mander said that behind Tarrants "warped" ideology was a "base hatred" that led him to attack defenseless men, women and children last year in New Zealands worst terror attack. "It is incumbent on the court to respond in a way that decisively rejects such vicious malevolence," Mander said as he announced a sentence unprecedented in New Zealand legal history. The judge said Tarrant had failed in his aim of promoting right-wing extremism as he gunned down victims in cold blood but the New Zealand Muslim community had still paid a terrible price. "It was brutal and beyond callous. Your actions were inhuman," the judge said. "Your crimes are so wicked, that even if you are detained until you die it will not exhaust the requirements of punishment and denunciation," Mander said as he announced the sentence. Tarrant -- a 29-year-old Australian white supremacist -- sparked global revulsion on March 15, 2019 when he rampaged through two Christchurch mosques for 20 minutes during Friday prayers. He had admitted 51 charges of murder, 40 of attempted murder and one of terrorism over the attacks, after reversing an initial not-guilty plea. Crown prosecutor Mark Zarifeh said the atrocity was "without comparison in New Zealands criminal history". "The offending was motivated by an entrenched racist and xenophobic ideology... in my submission, the offender is clearly New Zealands worst murderer," he said. Zarifeh said life behind bars was "the only proper sentencing option" for Tarrant. "No minimum period is sufficiently long to satisfy sentencing objectives given the gravity of the offending and the devastating loss of life and injury," he said. Throughout the sentencing, Tarrant remained impassive as the court heard harrowing testimony from dozens of his victims and their families. The atrocity shocked New Zealand and prompted Prime Minister Jacinda Ardern to immediately tighten gun laws and pressure social media giants to curb online extremism. She welcomed the life sentence on Thursday, saying Tarrant deserved a lifetime of "complete and utter silence". "The trauma of March 15 is not easily healed but today I hope is the last where we have any cause to hear or utter the name of the terrorist behind it," said Ardern, who was widely praised for her response to the attacks.