President Trump on Friday signed an executive order that he said would provide a thorough vetting of refugees to ensure that "radical Islamic terrorists" cannot get into the United States. Trump is following through on his pledge to set a hardline stance on national security, but the new policy was denounced as discriminatory and unconstitutional by human-rights groups and Democrats. "I'm establishing new vetting measures to keep radical Islamic terrorists out of the United States of America,” Trump said at a signing ceremony at the Pentagon, hours before the text of his order was released.

"We don't want them here. We want to ensure that we are not admitting into our country the very threats our soldiers are fighting overseas. We only want to admit those into our country who support our country and love deeply our people." Trump's order indefinitely blocks refugees from war-torn Syria from entering the U.S. and suspends all refugee admissions for 120 days while the administration determines which countries pose the least risk.

Admission will resume only after vetting has been deemed "adequate" by the secretary of State, the secretary of Homeland Security and Director of National Intelligence.

It also caps total refugee admissions for fiscal year 2017 at 50,000 — less than half of the 110,000 proposed by former President Barack Obama.

Trump's order declares the entry of Syrian refugees "detrimental" to U.S. interests and denies their entry "until such time as I have determined that sufficient changes have been made to the [U.S. Refugee Admissions Program] to ensure that admission of Syrian refugees is consistent with the national interest."

The U.S. already has the most stringent vetting system for refugees in the world, with the screening process taking 18-24 months on average. But Trump and others viewed the program as a security risk.

Trump's order Friday also imposes a 90-day ban on entry to the U.S. for visitors hailing from “countries of particular concern” when it comes to terrorism. The ban would apply to seven Muslim-majority countries: Iran, Sudan, Syria, Libya, Somalia, Yemen and Iraq. Those countries are designated as countries of concern by the Department of Homeland Security. It calls on the administration to compile a list of countries that do not meet vetting standards that would be "recommended for inclusion on a Presidential proclamation that would prohibit the entry of foreign nationals" from those nations until they are in compliance.

When refugee admissions resume, Trump ordered his administration to prioritize claims “made by individuals on the basis of religious-based persecution, provided that the religion of the individual is a minority religion in the individual's country of nationality.”

Updated: 8:57 p.m.