Crowds reportedly chanted "change, change, regime change" and "democracy for Iran" with green, white and red flags with lion and sun emblems waving in the air with a few "Make Iran Great Again" red hats spotted.
On Friday, President Trump said regime change in Iran would be the "best thing" to happen while speaking to troops at Fort Bragg in North Carolina.
"People are hoping that, at some point, the decision will be made that there's no use, there's no point, we're not going to get anywhere with negotiations," said Pahlavi. "Intervention is a way to save lives."
"There's no negotiating with these people in my view. They're hell-bent on enacting an agenda based on religion that teaches them to lie, teaches them to destroy in the name of God," said Graham.
He shared that the regime is the weakest it has been since 1979, adding, "It is a regime with American blood on its hand." And he called on protesters to "keep protesting."
The senator also took the stage at the Global Day of Action, speaking to the crowd and holding up a black "Make Iran Great Again" hat.
Large demonstrations were also held in Toronto, Melbourne, Athens, Tokyo, London and Los Angeles.
An estimated 350,000 people marched on the streets of Toronto, the city’s police spokesperson, Laura Brabant, told The Associated Press.
Iranian American activist and Beverly Hills plastic surgeon Sheila Nazarian told Fox News Digital the protests across the globe represent a universal truth.
"When regimes silence their people, the people eventually find their voice. Whether in the streets of Tehran or in diaspora communities around the world," she said.
Nazarian left Iran when she was 6 years old along with her family.
"As someone who came to this country from Iran, I know firsthand that these protests are not about politics. They’re about basic human dignity, women’s rights and the fundamental freedom to live without fear," she added.
The Associated Press and Reuters contributed to this report.