Mohan Ibrahim, who was in the area of the mosque, told the New Zealand Herald: "At first we thought it was an electric shock but then all these people started running".
At least 30 people have reportedly been injured or killed by a gunman according to reports.
The video footage widely circulated on social media, apparently taken by a gunman and posted online live as the attack unfolded, showed him driving to one mosque, entering it and shooting randomly at people inside.
Members of the Bangladesh cricket team had just arrived by bus at Masjid Al Noor mosque for Friday afternoon prayers when they heard gunshots.
"They told me that five people died over there in that mosque, and I have seen with my own eyes, three people dead on the street", he said.
TVNZ quoted the police as having confirmed that there have been multiple fatalities, and that there still is an active shooter scenario playing out.
Bangladesh's squad were disappointed their tour to New Zealand had been cut short by the shootings.
Mercedes 0.8s clear in FP2 in Melbourne
It was a tricky second session for the inexperienced drivers, with Alexander Albon again making errors after his crash in FP1. Alfa Romeo's Kimi Raikkonen was fifth quickest - just 0.099secs behind his former Ferrari team-mate Vettel.
Trump wields first presidential veto to nix border emergency rebuff
American Civil Liberties Union, which filed one of the cases, said the veto was meaningless - like the declaration in the first place .
Marvel debuts new 'Avengers: Endgame' trailer
A new trailer for the latest instalment of the Avengers series has landed, and we're all very excited. The Avengers just did to everyone what they hope to do to Thanos: caught us completely off guard.
"Police are responding with its full capability to manage the situation, but the risk environment remains extremely high", he said.
She said police were working to get the situation under control. It was an unprecedented act of violence.
"One man had been shot twice - once in the abdomen and once in the shoulder. he was conscious". "I couldn't put it into words how I'm feeling right now", said Williams, wiping away tears as he spoke. "We came and ran to the ground". "Some were covered in blood".
"We are shocked and appalled as I'm sure all New Zealanders are", White said.
An eyewitness says a man wearing a helmet and glasses and a military style jacket opened fire inside the mosque.
The local police have also cleared Cathedral Square, where thousands of children were rallying for action on climate change.
He added: "When we realised that the shooters could have inflicted more damage if they had found us inside the bus all at once, we took a collective decision to escape through the back gate. This has occurred in a place where people should be safe and they weren't". Liton Das and Nayeem Hasan were also back in the hotel and have been contacted, and told to stay back at the hotel.
The team stayed in their bus when the players saw signs of the attack. The players were kept on the bus by police but later allowed to leave and to walk to Hagley Oval.