New Zealand police said they have detained four people in connection with the deadly shootings and had secured a number of improvised explosive devices.
Police said two mosques packed with worshippers were targeted in the attack that Prime Minister Jacinda Ardern said marked 'one of New Zealand's darkest days.'
He said the suspected IEDs found attached to the attackers' vehicles had been made safe by the military.
The gunman — who documented the attack in a horrifyingly graphic video circulated online — was a right-wing extremist with Australian citizenship according to Prime Minister Scott Morrison.
Morrison said the shooting in Christchurch was carried out by 'an extremist, right-wing, violent terrorist' who was an Australian-born citizen.
Police have since lifted a lockdown that was placed on the city as authorities hunted for the assailants.
In a social media post just before the shooting, an online account suspected to belong to one of the attackers linked to an 87-page manifesto filled with anti-Muslim and anti-immigrant rhetoric and motivations for an attack.
Within the manifesto, which as not been officially confirmed to belong to the attacker, the author said he identifies as a supporter of Donald Trump 'as a symbol of renewed white identity and common purpose.'
'It is clear that this is one of New Zealand's darkest days,' she told reporters. 'Clearly, what has happened here is an extraordinary and unprecedented act of violence.'
An eyewitness told Radio New Zealand he heard shots fired and four people were lying on the ground, with 'blood everywhere'.
ESPN Cricinfo reporter Mohammed Isam said members of the Bangladesh cricket team, who are due to play a Test match in Christchurch tomorrow escaped from the mosque.
'They ran back through Hagley Park back to the Oval,' he tweeted.The Masjid al Noor in central Christchurch was filled with worshippers, when the attack happened, as was a second mosque in suburban Linwood.
A Palestinian man in the mosque, who did not want to give his name, said he saw a man 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,' he told AFP.
'Then people started running out. Some were covered in blood.'
Another witness told stuff.co.nz he was praying in the Deans Ave. mosque when he heard shooting and saw his wife lying dead on the footpath outside when he fled.
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