People holding so-called green cards, making them legal permanent United States residents, are included in President Donald Trump's executive action temporarily barring people from seven Muslim-majority countries from entering the United States, a Department of Homeland security spokeswoman said on Saturday.

"It will bar green card holders," Gillian Christensen, acting Department of Homeland Security spokeswoman, said in an email.

US President Donald Trump signed a sweeping new executive order Friday to suspend refugee arrivals and impose tough new controls on travellers from seven Muslim countries.

Making good on one of his most controversial campaign promises, and to the horror of human rights groups, Trump said he was making America safe from “radical Islamic terrorists”.

“This is big stuff,” he declared at the Pentagon, after signing an order entitled: “Protection of the nation from foreign terrorist entry into the United States.”

Trump's decree suspends the entire US refugee resettlement programme for at least 120 days while tough new vetting rules are established.

These new protocols will “ensure that those approved for refugee admission do not pose a threat to the security and welfare of the United States”. In addition, it specifically bars Syrian refugees from the US indefinitely, or until the president himself decides that they no longer pose a threat.

Meanwhile, no visas will be issued for 90 days to migrants or visitors from seven mainly-Muslim countries: Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.