Alexandria Ocasio-Cortez and Joaquin Castro have announced new legislation they intend to introduce as part of an effort to block Donald Trump’s national emergency declaration over the US-Mexico border.

The Democratic politicians pointed to the National Emergencies Act that provides Congress the ability to “terminate the President’s emergency declaration”, according to Mr Castro.

In a tweet following the announcement, Ms Ocasio-Cortez, a progressive freshman representative from New York City, wrote: “@JoaquinCastrotx and I aren’t going to let the President declare a fake national emergency without a fight.”

The legislation was announced shortly after the president held an event in the White House Rose Garden where he declared a national emergency and begrudgingly agreed to sign a congressional spending bill that did not include the billions of dollars he had requested for a wall to be built across the nation’s southern border.

“The order is signed,” the president declared on Friday. “We will have a national emergency and we will then be sued, and they will sue us in the 9th Circuit, even though it shouldn’t be there, and 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.”

Mr Trump added that he hoped the nation’s highest court would provide a “fair shake” as an exhaustive legal battle now emerges surrounding one of his most fundamental campaign promises.

The president’s move followed a rare show of bipartisanship when lawmakers voted Thursday to fund large swaths of the government and avoid a repeat of this winter’s debilitating five-week government shutdown.

His insistence on wall funding has been a flashpoint in his negotiations with Congress for more than two years, as has the resistance of lawmakers in both parties to meeting the president’s request. West Wing aides acknowledged there was insufficient support among Republicans to sustain another shutdown fight, leading Mr Trump to decide to test the limits of his presidential powers.

Story continues

In a statement posted to Twitter, Mr Castro said “dozens” of other Democratic lawmakers have signed onto the bill seeking to block the president’s national emergency. However, it remains unclear whether any Republicans will support the measure.

Mr Trump’s vision for the wall already has been substantially scaled down since his campaign for the White House, when it was to be built of concrete and span the length of the 1,900-mile border and be paid for by Mexico. Now, he’s looking to build “steel slats” along about half of the 1,900-mile stretch, relying on natural barriers for the rest. Previous administrations constructed over 650 miles of barriers.

The White House said the president would not try to redirect federal disaster aid to the wall, a proposal they had considered but rejected over fears of a political blowback.

Additional reporting by AP