He said they had disabled one and were in the process of disabling the second.
New Zealand's National Security Threat has been raised from low to high for the first time in its history.
Tarrant, and another gunman targeted two mosques during the bloodbath, injuring at least twenty people. "And you should condemn this not only as a hate crime but as a white supremacist terrorist attack". "It unites us against extremism, hatred and terrorism, which knows no religion".
Four people have been detained, and one is Australian. Almost 50 people were shot dead and dozens more injured when Tarrant open-fired on the mosque during a traditional Friday prayer known as Jummah.
Prime Minister Scott Morrison of Australia said that one of them was Australian.
"Police are aware there is extremely distressing footage relating to the incident in Christchurch circulating online", New Zealand Police tweeted.
PM Imran added "I blame these increasing terror attacks on the current Islamophobia post-9/11 where Islam & 1.3 bn Muslims have collectively been blamed for any act of terror by a Muslim". He described the gunman as "an extremist, right-wing, violent terrorist".
The Bangladesh cricket team - which had been in Christchurch for a test match against New Zealand that was later cancelled - all escaped without injury.
The foreign ministry says there are 330 Indonesian citizens in Christchurch, 130 of them students.
Three other people - two men and a woman - were also arrested.
Police departments in New York City, Los Angeles and San Francisco said extra precautions will be taken at mosques beginning Friday, and London Mayor Sadiq Khan offered condolences and reassurances to the city's Muslim community.More news: 'At least 10 children' in collapsed Lagos building
He then exited the mosque through the front door - after just under three minutes inside and headed into the street - firing random shots as cars drove past.
Police Commissioner Mike Bush said: "A serious and evolving situation is occurring in Christchurch with an active shooter".
"It is clear that this is one of New Zealand's darkest days", she told reporters.
Police have asked for people to stop sharing the footage, and that it was looking to get as much of it removed.
A man who claimed responsibility for the shootings left a 74-page anti-immigrant manifesto in which he explained who he was and his reasoning for his actions.
Social media platforms including Facebook are facing harsher scrutiny after a shooter accused of killing 40 people in two mosques in New Zealand appeared to livestream the murders over the internet. "This is absolutely tragic", Bush said of the incident.
Police did not identify those taken into custody and gave no details except to say that none of them had been on any watch list.
30 people are confirmed to have been killed inside the Al Noor mosque on Deans Avenue in Christchurch's west.
'We managed to get her into the vehicle of one of the people who was helping and got her to the hospital, she was critical, ' he told RNZ.
Just before the alleged gunman opened fire, he urged viewers to subscribe to the popular YouTube channel PewDiePie, which itself has been criticized for posting offensive footage in the past.
49 people have been confirmed to have been killed and another 48 individuals are being treated in hospital care as a result of the horrendous Christchurch, New Zealand mosque shooting.