Prime Minister Jacinda Ardern has paid tribute to the lives lost 20 years on from September 11 in the US.
Nearly 3000 people were killed and 25,000 others were injured after four commercial airliners were hijacked in terrorist attacks by al-Qaeda in 2001.
"Twenty years ago I was a student studying at Arizona State University when 9/11 happened," Ardern said on Instagram on Saturday evening.
"I remember it like it was yesterday - it felt like the whole world was going to change, and it did."
She said she kept the front page of the Arizona Republic newspaper the day after the event.
"It travelled home to New Zealand with me, and has moved around different flats and houses ever since.
"Probably proof of the profound impact my history teacher had on me, but also a reflection of the impact of that day."
It follows US President Joe Biden's recorded message calling on citizens to be united.
"At our most vulnerable...unity is our greatest strength," he said.