Rep. Alexandria Ocasio-Cortez has vowed to introduce a bill to block President Trump’s declaration of a national emergency for his southern border wall.

“@JoaquinCastrotx and I aren’t going to let the President declare a fake national emergency without a fight,” she tweeted on Friday morning.

Rep. Joaquin Castro released the following statement on Thursday, ahead of Trump's announcement:

“If President Trump declares a national emergency to fund his border wall, I’m prepared to introduce a resolution to terminate the President’s emergency declaration.”

Castro tweeted the following Friday morning shortly after Trump's press conference:

Meanwhile, Speaker Nancy Pelosi and Senate Democratic Leader Chuck Schumer released a joint statement on President Trump declaring a national emergency:

“The President’s unlawful declaration over a crisis that does not exist does great violence to our Constitution and makes America less safe, stealing from urgently needed defense funds for the security of our military and our nation. This is plainly a power grab by a disappointed President, who has gone outside the bounds of the law to try to get what he failed to achieve in the constitutional legislative process.

“The President’s actions clearly violate the Congress’s exclusive power of the purse, which our Founders enshrined in the Constitution. The Congress will defend our constitutional authorities in the Congress, in the Courts, and in the public, using every remedy available.

“This issue transcends partisan politics and goes to the core of the Founders’ conception for America, which commands Congress to limit an overreaching executive. The President’s emergency declaration, if unchecked, would fundamentally alter the balance of powers, inconsistent with our Founders’ vision.

“We call upon our Republican colleagues to join us to defend the Constitution. Just as both parties honored our oath to protect the American people by passing the conference committee bill, the Congress on a bipartisan basis must honor the Constitution by defending our system of checks and balances.

“The President is not above the law. The Congress cannot let the President shred the Constitution.”