Administration officials said all refugee candidates will now face enhanced security screening that will gather more biometric and personal information, including social media use. The measures will also allow for more diligent information sharing among the U.S. agencies tasked with vetting refugee applicants, officials said.
"These new measures are part of the administration's effort to raise national security standards for all persons traveling to the United States, and they are designed to intensify screening to keep nefarious and fraudulent actors from exploiting the refugee process to enter the United States," Homeland Security officials said in a statement.
During the additional 90-day review period for the 11 high-risk nations, applications from those countries will be considered on a limited case-by-case basis, according to administration officials. Those applicants could be accepted if they conclusively pose no threat and admitting them is determined to be "in the interest of the United States."
Officials refused to identify the 11 nations that are considered "higher risk," but they are presumed to include the Muslim-majority countries that have been targeted by the administration for travel restrictions. Federal courts have largely blocked those attempts.
Jennifer Higgins, a senior DHS official who works on refugee issues, said the United States will also deploy more officers abroad who are trained in "assessing the credibility and admissibility of applicants," including a more rigorous criminal background check or "ties to bad actors." Higgins said the goal would be to develop "tailored lines of questioning for each case."
A State Department official said Tuesday the United States will continue to view the "vulnerability" of applicants as the primary criterion for determining whether they should qualify as refugees. The government is also considering additional funding to help refugees already admitted to the United States to improve their language and work skills, the official said.
The new rules do not adjust the number of refugees the United States will accept in the next 12 months, which Trump has limited to 45,000, the lowest level since the Refugee Act was created in 1980.
On the campaign trail, Trump told supporters that a "massive inflow of refugees" was pouring into the United States and warned that extremists could be hiding among them.
"We don't want them here," he said, insisting that the United States needed new rules "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 will support our country and love deeply our people," he said.
Tuesday's executive order cited such justifications for the tougher measures, and said more than 300 U.S. refugees who have entered the United States have been the subjects of FBI counterterrorism investigations.
Since Congress created the Federal Refugee Resettlement Program, about 3 million refugees have resettled in the United States, according to the Pew Research Center.