Sessions told law enforcement officers at a conference in Sacramento Wednesday that the Justice Department sued California because state laws are preventing federal immigration agents from doing their jobs.
California leaders strongly deny that claim.
Sessions strongly criticized Oakland Mayor Libby Schaaf for her recent unusual public warning that an operation by federal immigration officers was imminent. He claims 800 "wanted criminals" eluded arrests as a result.
Sessions says California's laws are unconstitutional and a "plain violation of common sense."
Filed last night, the Justice Department lawsuit is focused on California's sanctuary laws for undocumented immigrants.
According to Immigration and Customs Enforcement, federal agents have targeted more than 230 undocumented immigrants in recent raids from Sacramento to the Bay Area.
Under California's sanctuary state laws, local law enforcement cannot be called on to help federal agents.
The California Peace Officers Association said the conflicting rules are creating confusion for police on the street and are now looking for Sessions to clarify those issues.
"It's a bit like a child being sent off to school or into public and being told to behave one way by their mother and another way by their father,” said former Sacramento Police officer John McGinness. “Well this needs to be clarified."
Sacramento Mayor Darrell Steinberg, however, made it clear where he stands on the issue speaking out from Washington DC.
"You can sue us, you can talk about jailing us, you can threaten us, you can seek to intimidate us it doesn't matter,” Steinberg said. “We are going to continue to be who we are proud to be and that is a city of inclusion, a city that protects immigrants."
Governor Brown responded in a statement saying "at a time of unprecedented political turmoil, Jeff Sessions has come to California to further divide and polarize America. Jeff, these political stunts may be the norm in Washington, but they don't work here."