Local police departments across the country are tracking cell phones without warrants, according to documents released by the American Cvil Liberties Union (ACLU) Monday.

Information from almost 200 state and local law departments revealed that only ten agencies do not track cell phones. Just six other departments require police to obtain warrants by showing probable cause, even as many other police departments are less strict in their rules. In Tucson, Arizona, for instance, police can obtain cell phone numbers for all phones in a particular place without warrants.

Catherine Crump, staff attorney for the ACLU Speech's Privacy and Technology Project, expressed her concerns with her organization's findings.

“What we have learned is disturbing," Crump said. "The government should have to get a warrant before tracking cell phones. That is what is necessary to protect Americans’ privacy, and it is also what is required under the Constitution. The fact that some law enforcement agencies do get warrants shows that a probable cause requirement is a completely reasonable and workable policy, allowing police to protect both public safety and privacy.”

The ACLU began its study in August 2011, with 35 affiliates of the organization filing over 380 requests under states' freedom of information laws.

The ACLU said that it supports a bipartisan law currently being pushed by members of Congress that would require police officers to obtain warrants to track cell phones or GPS devices.