Congress’ two top Democrats say they’ll use “every remedy available” to oppose President Donald Trump’s declaration of an emergency to shift billions of federal dollars into building a wall along the U.S.-Mexico border.

House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer said Friday they’ll take action “in the Congress, in the Courts, and in the public.”

They say Trump’s decision to declare an emergency is unlawful. They say it would “shred the Constitution” by usurping Congress’ power to control spending.

White House officials say some of the money would come from military construction projects. Pelosi and Schumer say Trump would be using money needed “for the security of our military and our nation.”

Democrats can file lawsuits and force congressional votes to block Trump’s money transfers. Trump could veto the legislation should it pass.

Trump says he expects legal challenges.