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 GrassleyGOP senators pitch alternatives after House pulls ObamaCare repeal bill Friends, foes spar in fight on Trump’s Supreme Court nominee Live coverage: Day three of Supreme Court nominee hearing 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 RubioSenators introduce new Iran sanctions Senate intel panel has not seen Nunes surveillance documents: lawmakers With no emerging leaders, no clear message, Democrats flounder MORE (Fla.), Pat RobertsPat RobertsDems mock House GOP over lack of women in healthcare meeting Perdue vows to be chief salesman for US agriculture abroad GOP senator apologizes for mammogram joke MORE (Kan.), John ThuneJohn ThuneLawmakers want infrastructure funded by offshore tax reform Senate GOP hedges on ObamaCare repeal timeline Week ahead: Robocall crackdown tops FCC meeting agenda MORE (S.D.) and Mark KirkMark KirkObamaCare repeal bill would defund Planned Parenthood Leaked ObamaCare bill would defund Planned Parenthood GOP senator won't vote to defund Planned Parenthood 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.