California's attorney general says at least a dozen states will join a lawsuit against President Donald Trump's emergency declaration to fund a wall on the U.S.-Mexico border.

Xavier Becerra told MSNBC's "Andrea Mitchell Reports" he planned to file California's lawsuit on Monday. He didn't specify which other states would join, but officials in Colorado, New Mexico and Nevada announced that they would challenge Trump.

Becerra says there is no emergency at the border and Trump doesn't have the authority to make the declaration.

Trump declared a national emergency to fulfill his promise of completing the wall.

The move allows the president to bypass Congress to use money from the Pentagon and other budgets.

California has repeatedly challenged Trump in court. Becerra has filed at least 45 lawsuits against the administration.