Internet providers have filed a lawsuit in the state of California in an effort to block its new net neutrality law from going into effect, adding momentum to a high-stakes legal fight over the future of the Internet.

The suit, filed Wednesday in a federal court, contributes to a legal challenge filed by the Justice Department on Sunday only moments after California Democrat Gov. Jerry Brown signed a bill imposing strict new requirements on Internet providers.

A new DOJ press release regarding the decision states Brown’s law “unlawfully imposes burdens on the Federal Government’s deregulatory approach to the Internet.”

“Under the Constitution, states do not regulate interstate commerce — the federal government does,” Attorney General Jeff Sessions said in a statement. “Once again the California legislature has enacted an extreme and illegal state law attempting to frustrate federal policy.”

After Brown’s passing of the law on Sunday, FCC Chairman Ajit Pai stated that “not only is California’s internet regulation law illegal, it also hurts consumers. The law prohibits many free-data plans, which allow consumers to stream video, music, and the like exempt from any data limits.”