"The offender was mobile. There were two other firearms in the vehicle that the offender was in, and it absolutely was his intention to continue with his attack," Ardern told a press conference in Christchurch.
A complex and comprehensive investigation into the attack was underway, Ardern pointed out.
"Thirty-nine people remain in hospital and 11 in ICU [intensive care units]. Those injured range from young children to the elderly. They include men, women and children and they were among those who have been both killed in and injured," the prime minister added.
The audio recording of Ardern's press conference was published by New Zealand Herald.
The shooter broke into two mosques in Christchurch on Friday, opening fire on those who were inside. Ardern said on Friday that 49 people had been killed in the attack.