WASHINGTON, United States (AFP) — US President Donald Trump signed an order Friday to strengthen the vetting of would-be immigrants or refugees and to keep “radical Islamic terrorists out of the United States of America.”

At a ceremony at the Pentagon to swear in James Mattis as his secretary of defense, Trump signed a decree entitled: “Protection of the nation from foreign terrorist entry into the United States.”

“This is big stuff,” he declared, to polite applause from gathered senior military brass.

The White House did not immediately make the wording of the decree public, but a draft text had been leaked to US media earlier in the week and was widely reported on.

According to this unconfirmed order, Trump’s decree suspends the entire US refugee resettlement program for at least 120 days while tough new vetting rules are established.

In addition, it specifically bars Syrian refugees from the United States indefinitely, or until the president himself decides that they no longer pose a threat.

Meanwhile, no visas will be issued for 30 days to travellers, whether would-be visitors or migrants, from seven mainly-Muslim countries: Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.

Civil liberties groups and many counterterror experts had condemned the measures in advance, arguing that it is inhumane to lump the victims of conflict in with the extremists who threaten them.

But the suspension of the program stops short of a threat Trump made during last year’s race for the White House to halt all Muslim travel to the United States.

Trump’s supporters defend the measures as necessary to prevent supporters of Al-Qaeda or the Islamic State group from infiltrating the US homeland disguised as refugees.