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 GrassleyDems plot recess offensive on ObamaCare The case for protecting America's intelligence agency whistleblowers Senate confirms Trump's first lower-court nominee 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 RubioSenate panel could pass new Russia sanctions this summer McConnell on Trump: 'We could do with a little less drama' Taking the easy layup: Why brain cancer patients depend on it MORE (Fla.), Pat RobertsPat RobertsGOP frustrated by slow pace of Trump staffing Senate GOP defends writing its healthcare bill in private GOP senators on Comey firing: Where they stand MORE (Kan.), John ThuneJohn ThuneCongress must address student loan debt crisis, a national economic drag Republicans go to battle over pre-existing conditions GOP frustrated by slow pace of Trump staffing MORE (S.D.) and Mark KirkMark KirkTaking the easy layup: Why brain cancer patients depend on it The Mideast-focused Senate letter we need to see The way forward on the Iran nuclear deal under President Trump 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.