WASHINGTON (NEXSTAR) — The federal government may not be able to keep communities from becoming sanctuary cities, but it could make it costly if a Republican senator has his way.

Sanctuary cities, counties, or other jurisdictions have laws and regulations that shield undocumented immigrants from US Immigration and Customs Enforcement—or ICE.

Sen. Patrick Toomey, R-Pennsylvania, says the sanctuary movement poses a threat to public safety. He is proposing a bill —which he calls the “Stop Dangerous Sanctuary Cities Act” – which would cut off large amounts of federal funding to the sanctuary governments.

“It’s crazy. They don’t belong here,” Toomey said. “We have dangerous criminals wandering the streets.”

Toomey says immigrant criminals are taking refuge in sanctuary cities, counties, or other jurisdictions that shield undocumented immigrants from US Immigration and Customs Enforcement—or ICE

Pennsylvania has multiple areas that are sanctuary jurisdictions, including the city of Philadelphia…

“We have the recent history of brutally violent criminals committing horrendous atrocities in Philadelphia after being released back on the streets, despite the fact that our federal immigration authorities wanted to take people into custody so that they could deport them,” Toomey said.

Critics of the proposed bill said cutting funding to cities would be counter-productive.

“To say we’re going to make it safer by cutting off law enforcement money to cities and states – that makes no sense at all,” said Sen. Patrick Leahy, D-Vermont. “Those of us who have served in law enforcement know you need the funds. Let the policymakers – the mayors, the governors, the legislatures – let them make the decisions they want.”

Toomey, however, says this is a matter of life and death.

“These people are in the business of committing crimes and violent crimes,” Toomey said.

Toomey’s bill faces an uphill battle, as it would need at least some Democratic support in both the Senate and the House to become law.