After some Iraqis that got admitted into the US were found to have created an IED when they lived in Iraq, Obama added new "more stringent vetting" to Iraqi immigrants, and it added a month-long delay to new visa approvals for Iraqis. The administration at the time would not admit it was an immigration block, just a delay.

If this is actually a temporary stop to figure out better vetting, or just pointless posturing, or a more long-term block, nobody outside the White House knows for certain.