US lawmakers announced late on Monday an agreement in principle to avoid another government shutdown, with nearly $1.4 billion in money for the construction of a wall on the border with Mexico.
The amount agreed is far less than Trump has demanded.
But if accepted, the deal would avert another chaotic standoff in which Trump has threatened to cut budgets from huge sections of government this Friday.
Senator Richard Shelby, a key Republican negotiator, told reporters an agreement in principle had been reached between Republican and Democratic lawmakers.
The agreement reportedly included $1.375 billion in funding for a wall on the US-Mexico border, a wall which was one of Trump's key campaign promises.
The US president had demanded $5.7 billion for his pet project.
The agreed figure would fund approximately 89 kilometers, all to be located in the Rio Grande Valley area of south Texas, according to aides.
The deal still faces White House approval.
The news came out just as Trump was about to climb the stage in the El Paso arena and the president, addressing a raucous crowd, said he did not have enough details to respond.
"We probably have some good news but who knows," he said.
Addressing thousands of people, many wearing his red "Make America Great Again" campaign hats, Trump said: "We need the wall and it has to be built and we want to build it fast."
Trump says illegal immigrants pose a national security risk to the United States and can only be stopped by dramatic extensions of current barriers.
