Attacks on two mosques in New Zealand left at least 40 dead Friday, with one gunman – identified as an Australian extremist -- apparently livestreaming the assault. Authorities detained four people. Witnesses spoke of victims being shot at close range, with women and children also believed to be among those killed. "It is clear that this can now only be described as a terrorist attack," said Prime Minister Jacinda Ardern about the events at Christchurch, adding it marked "one of New Zealands darkest days".  "From what we know, it does appear to have been well planned," she said, adding that in addition to the dead another 20 people were seriously injured.  The gunman at one mosque was an Australian-born citizen, Australian Prime Minister Scott Morrison said in Sydney, describing him as "an extremist, right-wing, violent terrorist". It was not immediately clear how many attackers were involved. Police Commissioner Mike Bush said police were not aware of other suspects beyond the four who were detained but they couldnt be certain. Morrison confirmed that one of the four people arrested was an Australian-born citizen. Two IEDS (improved explosive devices) were also found and neutralized by the military, police said. A Palestinian man who was in one of the mosques said he saw someone being shot in the head. "I heard three quick shots, then after about 10 seconds it started again. It must have been an automatic -- no one could pull a trigger that quick," the man, who did not wish to be named, told AFP. "Then people started running out. Some were covered in blood," he said, adding that he joined the fleeing crowd and managed to escape. The deadliest attack occurred at Al Noor Mosque in central Christchurch. Arden said 30 people were killed there. A video that was apparently livestreamed by the shooter shows the attack in horrifying detail. The gunman spends more than two minutes inside the mosque spraying terrified worshipers with bullets again and again, sometimes re-firing at people he has already cut down. He then walks outside to the street, where he shoots at people on the sidewalk. Childrens screams can be heard in the distance as he returns to his car to get another rifle. The gunman then walks back into the mosque, where there are at least two dozen people lying on the ground. After walking back outside and shooting a woman there, he gets back in his car. The singer bellows, "I am the god of hellfire!" and the gunman drives away. The video then cuts out. There was a second shooting at the Linwood Mosque that Ardern said killed 10 people.