Democratic and Republican politicians have sharply criticised President Trump’s plan to use emergency powers to pay for a border wall with Mexico.
Mr Trump is due to declare the emergency shortly in an attempt to bypass Congress, which has refused to approve $5.7bn (£4.4bn) for the wall.
Senior Democrats accused the president of a “gross abuse of power”. Several Republicans also voiced concern.
Building a border wall was a key pledge in Mr Trump’s election campaign.
Declaring a national emergency would give Mr Trump access to billions of dollars for his project.
The president agreed on Thursday to sign a spending bill that does not include finance for the wall.
Disagreement over the issue led to a 35-day government shutdown early this year the longest in US history.
The spending bill is due to be signed shortly to avert another shutdown. Citing unnamed White House officials, US media outlets reported that the president would sign the emergencies act at the same time.