WELLINGTON, March 17 (Xinhua) -- New Zealand Prime Minister Jacinda Ardern said on Sunday that the bodies of those killed in terror attacks on two Christchurch mosques were being returned to their families but only a small number at this stage.

She expected that all the bodies would be returned to families by Wednesday.

The suspect Brenton Tarrant was being held in a high-security facility, Ardern told a press conference.

There would be an increased police presence in Christchurch, the country's second largest city on Monday, with an extra 120 officers, she said, adding all mosques would be guarded by the police.

Specialist teams would be at Christchurch schools and early learning centers, and support lines were also available to anyone who needed it, Ardern said.

The parliament would also pay tribute to the victims on Tuesday.

Ardern paid tribute to police, hospitals, first responders and teachers following the mass shootings.

The prime minister said she would not stop the sales and advertising of firearms as suggested by academics, but she reiterated that there would be changes to the country's gun laws.

Ardern confirmed her office was one of more than 30 that received an email from the suspected shooter nine minutes before the attack took place, saying "it did not include a location, it did not include specific details."

The prime minister said she had sought advice on the possibility of the suspected gunman being deported, adding charges and the trial itself would absolutely be conducted in New Zealand.

A gunman stormed two mosques in Christchurch on Friday afternoon, killing at least 50 people and wounding 50 others.