As Christchurch's Muslim community reels from a devastating attack on two mosques that killed at least 49 worshippers and wounded dozens others, the New Zealand city has begun digging graves for the victims of the deadliest mass shooting in the country's history.Excavators were called in on Saturday to remove the vast amount of earth needed to bury the dead, although police have yet to release some of the bodies to families.A 28-year-old Australian identified as Brenton Harrison Tarrant has been charged with murder after the shootings at the Al Noor and Linwood mosques, in what New Zealand's Prime Minister Jacinda Ardern called a "terrorist attack".Al Jazeera's Wayne Hay, reporting from Christchurch, said both sites were still an active crime scene."Police are continuing their forensic work in an around the mosques. While that has been happening, some of the bodies have been taken out and returned to their family members so that their burial and funeral arrangements can begin as quickly as possible," he said.Hearses were need arriving and leaving the mosques. Outside the Al Noor mosque, where most of the victims died, a steady stream of hundreds of people laid flowers and lit candles at a makeshift memorial, some standing quietly, others crying or visibly distressed. Among those gathered were survivors of the attack.Ahmed Khan said one of his friends - a man he identified as Imran from India - was shot by the gunman."One bullet on his shoulder, so I was holding him." he said. "And then the gunman put the gun through the window and shot him. While he was on my lap, he shoot him - a couple of bullets in the head."Abdi Shaik, another survivor, said: "He was shooting us until he finished the bullets. When he finished the bullets, he left the gun over there and he ran away."At the makeshift memorial, many offerings were accompanied by handwritten letters laden with sadness and disbelief. "I am so sorry that you were not safe here. Our hearts are breaking for your loss," read one of the notes. Ardern, the prime minister, arrived in the city on Saturday and met with survivors and victims' families to offer sympathy and support.She said the victims came from across the Muslim world, with Turkey, Bangladesh, Indonesia and Malaysia among the countries rendering consular assistance.The members of Christchurch's Muslim community were advised to stay away from mosques while New Zealand's security alert remained at the second-highest level on Saturday.Meanwhile, doctors in a Christchurch hospital worked round the clock to treat 39 people for gunshot wounds and other injuries sustained in the attacks.The wounded included a two-year-old boy and a four-year-old girl, who was in critical condition.As messages of condolences and condemnation kept pouring in from around the world, more details emerged about the victims of the attack.Pakistan's foreign minister said at least six Pakistanis were killed, naming them as Sohail Shahid, Syed Jahandad Ali, Syed Areeb Ahmed, Mahboob Haroon, Naeem Rashid and Talha Naeem.Egypt and Jordan each said four of their nationals were killed. At least one Saudi citizen was also among the dead.In Bangladesh's capital, Dhaka, State Minister for Foreign Affairs Shahriar Alam told reporters on Saturday that "a total of 10 people of Bangladeshi origin were affected" in the attack."Two of them died instantly and three others were missing," Alam said, adding that the five others were wounded."There are around 300 people of Bangladeshi origin living in Christchurch. They are all being asked to stay inside their home. The situation in the city is still very intense," he said. Tarrant, the accused attacker, appeared unrepentant in a Christchurch District Court on Saturday, staring down media members with a smirk on his face. He was remanded without a plea until his next appearance in the South Island city's High Court on April 5.He did not speak but flashed an upside-down "okay" signal, a symbol used by white power groups across the globe.Judge Paul Kellar allowed photos to be taken but ordered that the face of the former fitness instructor be blurred to preserve fair-trial rights. Two other suspects were taken into custody while police tried to determine what role, if any, they played in the cold-blooded attack that stunned New Zealand.One man, 18-year-old Daniel Burrough, has been charged with incitement.None of those arrested had a criminal history or was on any watchlist in New Zealand or Australia.Ardern said the shooter was "in possession of a gun licence" obtained in November 2017, and he started legally purchasing two semi-automatic weapons, reportedly AR-15s, two shotguns and a lever-action gun the following month.Ardern said some of the guns had been modified to make them deadlier."I can tell you one thing right now - our gun laws will change," she said.