The leader of the largest police union in the U.S. has expressed concerns over President Trump’s planned federal grant cuts to cities that don’t cooperate with federal immigration authorities. Jim Pasco, the executive director of the Fraternal Order of Police, told Reuters on Tuesday that while he doesn’t agree with the policies of sanctuary cities, he does believe funding cuts to those cities could threaten public safety. Pasco’s comments come after Attorney General Jeff Sessions said Monday that the Justice Department will cut off grants to cities that do not assist federal authorities in detaining undocumented immigrants. Pasco said he met with Sessions, Trump, and Vice President Mike Pence on Tuesday, and Trump offered reassurances that public safety would not be undermined. But Sessions’s announcement Monday stressed that “compliance” with federal immigration law would be “a condition for receiving” federal grants, a policy that Pasco said he told Sessions the police union would oppose last month.