WASHINGTON - On Sunday morning in a city on the east coast of the United States, an Iranian man who has been in the US for 14 years, has a PhD, and is a green card holder, woke up to the reality that for the foreseeable future, his 60 year old mother who still lives in Iran, would not be coming to see him again, and he will not be able to go and see her again.

He is not alone. Up to 500,000 legal residents of the US are affected by President Donald Trump's executive order on Friday, blocking citizens from predominantly Muslim Iran, Iraq, Syria, Yemen, Sudan, Libya from the US for 90 days and suspending entry of all refugees to the United States for 120 days - and barring Syrian refugees indefinitely.

"It (the order) will bar green card holders," Gillian Christensen, acting Department of Homeland Security spokeswoman, said in an e-mail to Reuters.

That means the Iranian professor would not be able to return to his wife, job and family if he leaves the US. He was "distraught" his wife said, asking that they not be named - a reflection of the uncertainty tinged with fear, among may immigrant communities in the US in the wake of President Donald Trump's executive orders - including one to build a wall on the Mexico border.

Reports are flooding in from across the world, of citizens of these countries - including Green Card holders - being disallowed from boarding flights. Google has reportedly recalled travelling staff members to the US.

The US' political division has just deepened, with ramifications increasingly beyond its borders.

Critics say the order, targeting Muslims, is unconstitutional. Records show little risk of terrorism from Muslim immigrants and refugees, and there is already a vetting process - which, however, Mr Trump wants to enhance.

The American Civil Liberties Union (ACLU) is suing the Donald Trump administration on behalf of two Iraqi men who were detained at New York's JFK International on Saturday (Jan 28), within hours of the presidential order.

One of them, Hameed Khalid Darweesh, was travelling on a special Immigrant Visa. He has worked as an interpreter, engineer and contractor for the US government in Iraq for 10 years, according to the case filed in New York's Eastern District Court.

The ACLU in a statement cited Brandon Friedman, a former Obama administration official who commanded a platoon during the invasion of Iraq, saying on Twitter that Mr Darweesh had worked for him as an interpreter and had "spent years keeping US soldiers alive in combat in Iraq".

Mr Darweesh was reported to have been released on Saturday afternoon.

The other, Haider Sameer Abdulkhaleq Alshawi, had been granted a Follow to Join Visa. "His wife and seven-year-old son are lawful permanent residents residing in Houston, Texas, and were eagerly awaiting his arrival. Mr. Alshawi's son has not seen his father for three years" the ACLU said.

"The refugee order represents a fundamental shift in the story we tell each other and the world about America," tweeted Mathew Gertz of Media Matters, a group that conservatives refer to as "far left".

"We have said that we welcome those fleeing persecution, for many of our forebears came here because they had been persecuted. Our history is replete with examples of our failure to live up to those statements. But it was nonetheless part of the American creed. Trump's order sets that story on its head."

On Friday evening, Senator Dianne Feinstein tweeted : "There is no legitimate reason to ban refugees - the vast majority of whom are women and children who have experienced absolute horror.

"I very much regret that the President has chosen this dark path for our country."

Analysts and commentators have not missed the irony that the executive order was issued on Holocaust Remembrance Day.

But Mr Trump's supporters had no such issues. They included Prime Minister Benjamin Netanyahu of Israel, who referring to the Mexican border wall - another controversial order which risks a full blown spat with Mexico, an economy that is intertwined with that of the US - tweeted : "President Trump is right. I built a wall along Israel's southern border. It stopped all illegal immigration. Great success. Great idea."

On the first day of the Chinese Year of the Fire Rooster, the world is seeing a different face of America.