A group of 23 states, led by California, sued the U.S. government in order to block ITS decision to prevent them from setting their own emission standards.

Apart from California, the states include New York, Michigan, Colorado, Illinois, New Jersey, Nevada, North Carolina, New Mexico, Oregon, Washington, Wisconsin, Pennsylvania, Michigan, Maryland and Massachusetts.

The U.S. Transportation Department and the National Highway Traffic Safety Administration determined that federal law preempts state and local fuel economy regulations, including California’s own standards that have been adopted by a dozen other states.

Also Read: EPA Revokes California’s Emissions Waiver, Launches “One National Program Rule”

The expected legal challenge from the 23 states doesn’t include a parallel decision by the EPA to revoke California’s 2013 Clean Air Act waiver to set emissions standards, which will not take effect until late November, Reuters reports.

The lawsuit was filed in the U.S. District Court in Washington and marks the beginning in the war that has been brewing between the Trump administration and state officials over the U.S. fuel economy and emissions standards.

“Mr. President, we’ll see you in court,” California Attorney General Xavier Becerra said in a statement. Becerra added that the Transportation Department’s determination was unlawful and that the Trump administration misread federal law and ignored the Congress, claiming that “the administration insists on attacking the authority of California and other states to tackle air pollution and protect public health”.