People around the world are expressing outrage and worry following an executive order from U.S. President Donald Trump that bars all refugees from seven nations from entering the country for four months.

Trump said the action is a way to keep out “radical Islamic terrorists” when he signed the order Friday, saying a suspension of the U.S. resettlement program will give his government time to impose stricter security checks for refugees entering the country.

The order imposed a 90-day immigration ban to the U.S. from those in Muslim-majority countries: Iraq, Iran, Sudan, Libya, Somalia and Yemen. Trump indefinitely banned refugees from war-torn Syria.

Former refugees, including some who came from one of the banned countries, weighed in on Saturday, noting that their accomplishments helped build up America as one of the world’s superpowers.

In a Facebook post on Thursday, U.S. doctor Mehran Arabpour wrote about leaving Iran 33 years ago to come to America as a teen with a student visa and “a dream of becoming a cardiologist.”

Arabpour said he washed dishes and flipped burgers at fast food restaurants and drove an ice cream truck to put himself through school.

“Today I am an interventional cardiologist, a US citizen from one of the countries whose citizens are banned from coming to US,” Arabpour wrote. “I have saved hundreds of lives in my career, have paid thousands if not millions in taxes, created many jobs, but my president thinks those like me don’t belong here.”

Arabpour’s post garnered more than 5,500 shares and hundreds of comments on Facebook, with many thanking Arabpour for his work in the U.S., and for being a “model” American-Iranian. However, some commenters defended Trump’s ban, saying it is only temporary and will serve to provide more thorough security checks for those entering the country.

33 years ago I was a 17 year old kid from Iran, arrived in US with a student visa and a dream of becoming a...

Posted by Mehran Arabpour on Thursday, January 26, 2017

Nobel laureate Malala Yousafzai, who in 2012 was shot in the head by Pakistani Taliban intent on ending her campaign for girls’ education, has also spoken out against the order, saying in a direct call-out of Trump that refugees and immigrants have “helped build your country.”

Yousafzai, a co-winner of the 2014 Nobel peace prize, said in a statement that she is “heart-broken” that America is “turning its back on a proud history of welcoming refugees and immigrants – the people who helped build your country, ready to work hard in exchange for a fair chance at a new life.”

She added: “I am heartbroken that Syrian refugee children, who have suffered through six years of war by no fault of their own, are singled-out for discrimination.”

Malala Yousafzai's statement on President Trump's latest executive order on refugees: "I am heartbroken that today...

Posted by Malala Fund on Friday, January 27, 2017

Others have pointed out over social media that if the ban had been implemented decades earlier, Apple Inc. co-founder Steve Jobs may never have been born. There have been many reports that Jobs’ biological father, Abdul Fattah Jandali, was a Syrian refugee who fled to the U.S. for political reasons.

Jobs, who was born in California but given up for adoption, did not have a relationship with Jandali.

Today, the late Jobs is considered a pioneer in personal computing and an inventor who helped revolutionize the way the world communicates via technology.

Joseph Humire, executive director of the Washington-based Center for a Secure Free Society, a non-partisan global research organization, said the “key” word in Trump’s order is “temporary.”

“It’s more to do with national security than it has to do with politics,” Humire told CTV News Channel on Saturday. “It has to do with getting a handle on the in-flows of refugees from the Middle East.

Humire added that there is a “lack of insight and information” that is coming from some Middle Eastern countries.

“We just don’t have the relationship with those governments to understand if the people coming into this country are who they say they are” Humire added. “It’s a technical deficiency that we have to get a handle on before we can actually go back to having refugees from those countries.”

But many organizations are decrying the order, calling it unconstitutional and discriminatory.

Lena F. Masri, national ligitation director for the Council on American-Islamic Relations told The Associated Press that there is “no evidence that refugees – the most thoroughly vetted of all people entering our nation – are a threat to national security. “This is an order based on bigotry, not reality.”

The organization said it would challenge the constitutionality of Trump’s ban.

Hopes dashed

Syrians hoping to flee their homeland, ravaged by a years-long civil war, saw their hopes dashed on Friday. That’s when Trump banned their entry to the U.S. indefinitely, pending a review of the admissions program.

Nearly five million Syrians have fled the country since war broke out in 2011. Millions more are displaced within the country, and in neighbouring nations, including Jordan, Turkey and Lebanon.

Syrian refugee Ammar Sawan, 40, said from Jordan that he submitted an initial round of security screenings three months ago. But his dream of moving to the U.S. is now in jeopardy.

“When we heard of the order, it was a bolt of lightning, and all our hopes and dreams vanished,” Sawan told The Associated Press.

He said he was planning to move to the States so that his four children could obtain a good education. Other refugees said they were shocked and saddened.

“We tell the American people that we hope (Trump) retracts his decision,” said 37-year-old refugee Mayada Sheik. “We are not going to harm people of other countries.”

With files from The Associated Press