Ali, a 33-year-old Iranian-American engineer and tech start-up consultant living in Los Angeles, has no idea when he might see his mother again.

Ali's mother, a 66-year-old retired school principal in Tehran who typically visits the United States once a year, is prohibited from entering the country for the next 90 days under President Donald Trump's landmark executive action on immigration.

The order bans citizens from the Muslim-majority countries of Iran, Syria, Iraq, Somalia, Sudan, Libya, and Yemen from entering the US. Trump's executive order also bans refugees for the next 120 days and bars Syrian refugees indefinitely.

When Ali, who was born in Tehran, turned on the television to learn the news on January 27, he says he was both stunned and devastated.

"I feel [utter sadness]," he said over the telephone from an Iranian restaurant in California.

"It's baffling … It is upsetting to me, it is upsetting to my wife and it is upsetting to my family. They live their own lives, they come visit for a short time and then they go back. They don't pose a threat to anybody, they don't cause harm to anyone, they love the culture in the US."

Ali, who has been a US citizen since 2013, and who had arrived in 2002 to study, asked to remain anonymous out of fear of reprisal in the US and for his family in Iran. His older sister also lives in Orange County and works in press relations.

Not long after moving to the US, Ali met Deborah, a writer and philanthropist from California. They married in 2008. He received his bachelor's degree in electrical engineering at California State University and later completed his master of business. He eventually became the vice president of a tech start-up in California before becoming a consultant.

"America is great," he explained. "It is the land of opportunity. You have the opportunity to do anything, to become anyone, to be successful, to contribute to society and I feel like I as a citizen and my wife as a citizen, we have done that. We have aspired to be successful. We contribute to society. I feel like with these executive actions it's thinning that shining city on the hill - the promised land that everybody looks to."

READ MORE: Immigration ban - Hope trumps fear for Iranian-Americans

Student detained

Early on January 29, a federal judge in Brooklyn issued an emergency stay on Trump's travel ban, allowing the release of hundreds of detained green-card holders and effectively blocking their deportation. Yet, hundreds, perhaps thousands, more remain in limbo around the world.

Vahideh Rasekhi, an Iranian linguistics PhD student at Stony Brook University in New York, was one of the hundreds detained across the country . She had travelled home in November and was returning to her graduate studies when she was held at Terminal 7 in John F Kennedy airport. Rasekhi told her friends that after she was held, American border officials forced her on to a plane bound for Kiev, Ukraine, despite the emergency stay on Trump's order.

"I get a message saying they are on a plane and taxiing and leaving the gate," said Thurlough Martin Smyth, 38, a friend and fellow student of Rasekhi at Stony Brook, who was in touch with her during the ordeal.

"I called her and said that there is a court order in effect which prevents your removal from the country so just get off the plane. She said, 'No one is listening to me. No one is paying attention, everyone is ignoring me.'"

Rasekhi's plane was reportedly taxiing on the runway when the aircraft was brought back to the terminal after lawyers from the International Refugee Assistance Project intervened. Following the traumatising ordeal, Rasekhi, who is also the president of the school's Graduate Student Organization, disembarked from the aircraft, and was eventually released.

"She is a really generous, warm, sociable [person]," Smyth added. "She cares about her research and just wants to come and finish what she started and be free to come and do that."

Dread and hope

Noora Mustafa , an 18-year-old high school senior and first generation Libyan-American from Houston, Texas, was equally stultified by Trump's move.

"I'm scared and feel betrayed by the country I've lived my whole life in," she said in a video. "It kind of bounces between straight up fear and bewilderment."

Mustafa fears for her brother-in-law, a Libyan national, US green card-holder, and orthopedic surgeon in his 30s who travels between Texas and Libya frequently to visit family.

"When can he see his family again?" she asked.

"My family and all of us are kind of shell-shocked in a way and we cannot believe that this is really happening. You feel like this would never touch you, especially when you are born and raised in America and this is the country you know you have a sense of pride [in]. And then when something like this happens, it kind of feels like your mum or dad are slapping you right in the face."

Malek Jandali, 44, a German-born Syrian-American pianist called the move "un-American".

"At first, it was disgusting - we were all anticipating this but when it actually happened it became reality," said Jandali, who performs at Carnegie Hall regularly and has a concert there on February 4. "Closing doors to the world's needy people is not what America should stand for."

Jandali's father, a retired surgeon, and mother, a former physics and chemistry professor, are Syrian refugees who fled Aleppo in 2011. They are currently awaiting their citizenship interviews, a process that has now been thrust into uncertainty. But the musician is optimistic American values will prevail in his parents favour.

"I am worried but at the same time I am optimistic because we have a constitution and I still believe in the American values of freedom, justice, [and] freedom of speech," he added.

Right to a normal life

More ambiguous is the future of Khaled and Sameer, a gay Syrian couple in Gaziantep, Turkey, who planned to arrive in the US sometime in the next month. After a gruelling two-year application process that involved passing interviews with Homeland Security, medical checks, and cultural orientation screenings, a stroke of Trump's pen has impeded their journey to begin a new life - all this after fleeing war-torn Aleppo and Homs. Both asked to remain anonymous to avoid persecution in Turkey for their sexual orientation.

"We are in shock," said Sameer. "I don't know what to say. We should be now preparing our stuff to travel. We've been waiting for two years. We have dreams. We have the right to live. We have the right to have normal lives. We are humans."

They fought back tears as they scrambled to articulate what they had lost - and what they would do next.

"Our dream of living freely somehow, just having some dignity, being able to walk out on the street holding hands or just not afraid that something might happen to us any minute - we were just hoping to be relieved from that feeling, you know?" said Khaled.

"And just to have all that taken away from us in a blink of an eye is crazy. It's scary. We feel lost. We don't know what to feel."

The couple is now considering transferring their visa referral to Canada.

Back in Los Angeles, Ali, the Iranian-American tech consultant, hopes to one day have children, but he shudders at the possibility that his his mother might not be there to share that moment, that is if Trump's ban stands after its 90-day debut.

"I would want my mother here when our newborn arrives, you know," he said. "It's heartbreaking."

In response to Trump's immigration ban, Iran announced "reciprocal measures", saying they will suspend visas for US passport holders until the US reverses Trump's executive order. The gravity of the political chain reaction has has left Ali wondering if he'll even be able to go back and visit his family, given his dual citizenship under the new American administration.

For now, Ali will hold on to the memories he does have of his mother in the US, who last visited in 2014.

"We go to sightseeing places," he reminisced. "We go to the beach, we go to Disneyland, we go for hikes, we take a road-trip together and she really embraces the culture of the US."

Dorian Geiger is a Canadian journalist, award-winning filmmaker, and a social video producer at Al Jazeera English. Follow him on Twitter and Instagram .