If I were President Trump I would sign an EO tomorrow morning that says that everyone who enters our country from those 7 countries must be detained at the airport, or at the Embassy for their country until they can be properly vetted. They would not be free to walk our streets until they are completely vetted, so come on in, but be prepared to be detained for as long as it takes.
They can’t be vetted. They have no papers and no one can prove who they are. Impossible to even keep track of them once they are here. Assad just said it: no one knows who they are.