Police chiefs from some of the nation’s largest cities have gathered in Washington to voice opposition to Arizona’s recent anti-immigrant law. The measure requires police officers to stop and interrogate anyone they suspect is an undocumented immigrant. On Wednesday, police chiefs from Los Angeles, Houston, Philadelphia and six other cities warned Attorney General Eric Holder that crime will increase if other states pass similar laws. Tucson Chief of Police Roberto Villaseñor said the law undermines police work.

Roberto Villaseñor: “When you enact legislation that makes any subset of that community feel like they are being targeted specifically or have concerns about coming forward and talking to police, that damages our capability to obtain information to solve the crimes that we need to work with. This is not the focus of local law enforcement. Immigration is the focus of the federal government, and by bringing local law enforcement into the picture, it damages that relationship that we have spent years cultivating to try and get us into a position where we can work well with our community.”

The police chiefs’ meeting with Holder has helped fuel speculation the Obama administration is preparing a federal lawsuit to challenge the Arizona law. Lawmakers in fifteen states are currently considering passing anti-immigrant laws similar to Arizona’s.