Reports say Democratic and Republican politicians have sharply criticised President Trump’s plan to use emergency powers to pay for a border wall with Mexico.
The rarely-used move would enable Mr Trump to bypass Congress, which has refused to approve the money needed.
Senior Democrats accused the president of a “gross abuse of power” and a “lawless act”.
Several Republicans also voiced concern at the plan.
Building a border wall was a key campaign pledge of Mr Trump’s 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 must be signed on Friday 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.