New Zealand Prime Minister Jacinda Ardern does "not understand" why the U.S. has not changed its guns laws despite the exponential increase in mass shootings in recent years. Ardern banned assault rifles throughout her country less than a month after its worst-ever mass shooting occurred in March.

"Australia experienced a massacre and changed their laws. New Zealand had its experience and changed its laws," Ardern told CNN's Christiane Amanpour in an interview Tuesday. "To be honest with you, I do not understand the United States."

Just days after the Christchurch shooting on two mosques that left 51 people dead, Ardern announced an impending ban on military-style semiautomatic weapons, assault rifles and high-capacity magazines. On April 10, New Zealand's parliament voted 119 to 1 to pass the gun control legislation.

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Her rapid action lies in stark contrast to the lack of federal gun control measures in the U.S. despite hundreds of mass shootings in recent years. "I could not fathom how weapons that could cause such destruction and large-scale death could be obtained legally in this country," Ardern said in April.

New Zealand Prime Minister Jacinda Ardern tells CNN's @camanpour that she does "not understand" why the United States has not passed stronger gun laws in the aftermath of mass shooting events https://t.co/dRmumzaIlQ pic.twitter.com/D1XMVfoDSg — CNN (@CNN) May 15, 2019

Ardern acknowledged New Zealand's previous "pretty permissive" gun laws and affinity for hunting, but "that does not mean that you need access to military-style automatic weapons and assault rifles. She said that New Zealanders mostly agree with the new legislation.

Australia acted similarly in the aftermath of the 1996 Port Arthur shooting, which left 35 people dead. Then-prime minister John Howard — a conservative politician and close friend of George W. Bush — passed sweeping gun control legislation just 12 days after the massacre. Since then, there has not been a single mass shooting in Australia.

Ardern is in Paris with French President Emmanuel Macron hosting a summit on curbing online extremism. The Christchurch massacre was live-streamed on Facebook and also appeared on Instagram, YouTube, Reddit and 8chan. Now, governments around the world are calling on social media giants to end the use of their platforms for acts of terrorism.

Since the start of 2019, 123 mass shootings have occurred in the U.S., according to the Gun Violence Archive. The Las Vegas shooting in October 2017 remains the deadliest in American history, when 59 people were killed and more than 500 were injured. With one exception, no major federal gun control measures have passed Congress since the 1990s.