CHRISTCHURCH, New Zealand, March 16 (Xinhua) -- New Zealand Prime Minister Jacinda Ardern said on Saturday that the suspect of the deadly mosque attacks used modified semi-automatic weapons.

She told a press conference in Wellington that there were still 39 people in hospital, 11 of whom in critical conditions.

The prime minister said the two police officers who arrested Brenton Tarrant, a 28-year-old Australian man, deserved plaudits for their bravery.

Tarrant was charged with murder Saturday morning.

The terrorist attack left 49 dead and 48 people wounded in two Christchurch mosques. Tarrant was apprehended along with two other Australian men.

Earlier in the day, Ardern said the country's gun law would be changed.

"Our gun law will be changed" said Ardern, noting that the killers had legitimate gun license.

Five guns were discovered, two of which were semi-automatic guns, she said. Other weapons and firearms were also retrieved by the police after the attacks on Friday.

Christchurch Mayor Lianne Dalziel on Saturday extended her condolences to the victims and their families and people who are affected by the attacks.

"Our thoughts go to the victims and their families and everyone that being affect," Dalziel told Xinhua, calling the event "an unspeakable tragedy." She also acknowledged the extraordinary response from the police and first responders.

"An attack on the Muslin community is an attack on us, on Christchurch and on New Zealand," Dalziel said.

She believed that Christchurch people will go through this together by "looking after each other ... in many diverse communities in our city."

"We need to make sure that everyone feels safe, and everyone feels welcome and everyone feels a part of the city," the mayor said.

Major public events during the weekend have all been cancelled across New Zealand after the attacks.