WASHINGTON – California and 15 other states sued President Donald Trump on Monday over his decision to declare a national emergency to free up funding for his controversial border wall, calling the move "unlawful and unconstitutional."

The states allege in their lawsuit that Trump's emergency declaration exceeds the power of the president and unconstitutionally redirects federal money that Congress had set aside for other purposes. Trump made the declaration on Friday after lawmakers sent him a government funding bill that included $1.375 billion for the wall, far short of the $5.7 billion he initially requested.

White House officials said they believe they can unlock an additional $6.6 billion through the emergency declaration and other budget maneuvers. The White House believes the money would allow the administration to build at least 234 miles of the border wall, which was a central promise of Trump's 2016 campaign.

“President Trump treats the rule of law with utter contempt," saidCalifornia Attorney General Xavier Becerra, a Democrat. "He knows there is no border crisis, he knows his emergency declaration is unwarranted, and he admits that he will likely lose this case in court."

White House officials did not immediately respond to a request for comment.

California filed the lawsuit in the Northern District of California, where appeals are heard by the 9th Circuit Court of Appeals. Trump has repeatedly claimed that his opponents would file litigation there, and he predicted on Friday that the appeals court would rule against him.

"They will sue us in the 9th Circuit," Trump told reporters in the White House Rose Garden on Friday. "We will possibly get a bad ruling, and then we'll get another bad ruling and then we'll end up in the Supreme Court."

The states' lawsuit is only the latest, and it's probably not the last. Hours after Trump signed the emergencydeclaration, the watchdog group Public Citizen filed a lawsuit in the District of Columbia. The suit was filed on behalf of Texas landowners who own property on the Rio Grande and others.

But the lawsuit filed by the states, whose attorneys general are all Democrats, will be especially important to watch, in part because of the legal resources attorneys general bring to major federal litigation and in part because of their standing to sue. The attorneys general argue in the suit that the president's moves will redirect drug interdiction money and other funds that would have gone to their states.

The states joining California are: Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Michigan, Minnesota, Nevada, New Jersey, New Mexico, New York, Oregon, and Virginia.