A group of five Republican senators on Thursday introduced legislation that would restrict those who live in Ebola-stricken countries from traveling to the United States, while allowing exceptions for some aid workers and foreign military members.

People who live in countries designated by the Centers for Disease Control and Prevention as having “widespread transmission of Ebola” would not be able to receive a visa to enter the United States, under the bill. Aid workers and foreign military authorized by the United States Agency for International Development and the Defense Department would be exempt. 

“To protect our security, we must stop Ebola at its source,” Sen. Chuck GrassleyChuck GrassleyWhite House clarifies: We condemn all violence Republican lawmakers criticize Trump response to Charlottesville Grassley reverses ‘expectation’ of Supreme Court vacancy this year MORE (R-Iowa) said in a statement. “The best way to make this happen is to cease issuing visas or restricting entry to people from countries that are most impacted.”

Grassley added that, “these countries simply don’t have the standards in place to properly screen travelers entering the United States.”

He is joined by Republican Sens. Marco RubioMarco RubioScarborough: Trump has chosen the 'wrong side' THE MEMO: Trump reignites race firestorm RNC spokeswoman: GOP stands behind Trump's message 'of love and inclusiveness' MORE (Fla.), Pat RobertsPat RobertsNo. 2 Senate Republican backs McConnell in Trump fight Overnight Healthcare: McConnell warns Senate not to block repeal debate | Insurers knock Cruz proposal | WH tries to discredit CBO | Lawmakers propose .1B NIH funding boost Trump: I’ll be ‘very angry’ if Senate doesn’t pass ObamaCare repeal bill MORE (Kan.), John ThuneJohn ThuneWaymo taps Senate Commerce staffer for government affairs team Billboard ads target Republicans who want to roll back net neutrality GOP debates tax cuts vs. tax reform MORE (S.D.) and Mark KirkMark KirkImmigration critics find their champion in Trump Trump's nominee to lead USAID has the right philosophy on international aid McConnell: Senate to try to repeal ObamaCare next week MORE (Ill.). All five senators, along with a slew of other lawmakers, have previously called for a travel ban. But the White House has resisted those calls and said that a ban could be counterproductive, encouraging travelers to lie about exposure to the virus.

Citing State Department figures, Grassley noted that the U.S. issued more than 6,300 visas to people from Liberia, Sierra Leone and Guinea from March until September 27. Those three countries would meet the guidelines for a travel ban under the bill and have been battling the current Ebola outbreak since March. 

Residents would be able to receive visas 60 days after the CDC says the virus is no longer rampant in their home country.