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 GrassleyCharles (Chuck) Ernest GrassleyGOP senators eager for Romney to join them Five hurdles to a big DACA and border deal Grand jury indicts Maryland executive in Uranium One deal: report 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 Antonio RubioOvernight Cybersecurity: Bipartisan bill aims to deter election interference | Russian hackers target Senate | House Intel panel subpoenas Bannon | DHS giving 'active defense' cyber tools to private sector Senators unveil bipartisan push to deter future election interference Puerto Rico's children need recovery funds MORE (Fla.), Pat RobertsCharles (Pat) Patrick RobertsGOP senators eager for Romney to join them Canada tamps down worries about US NAFTA withdrawal Canada worried Trump will withdraw from NAFTA: report MORE (Kan.), John ThuneJohn Randolph ThuneWeek ahead: Tech giants to testify on extremist content Overnight Tech: GOP senator presses Apple over phone slowdowns | YouTube cancels projects with Logan Paul after suicide video | CEOs push for DACA fix | Bill would punish credit agencies for breaches GOP senator presses Apple on phone slowdowns MORE (S.D.) and Mark KirkMark KirkHigh stakes as Trump heads to Hill Five things to watch for at Trump-Senate GOP meeting Giffords, Scalise highlight party differences on guns 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.