With senators racing against a self-imposed end-of-the-week deadline to strike a deal, Trump demanded the chamber rally around his proposal, which puts the "Dreamer" immigrants who were brought to the country illegally as children on a pathway to citizenship -- but severely curtails legal immigration.
Trump's hard line was imperilling the prospects of a deal, as he urged senators to oppose a series of bipartisan efforts, including one gaining traction.
The president's plan protects Dreamers and boosts border security funding, but also abolishes the diversity visa lottery and restricts family reunification, a policy Trump calls "chain migration."
In a statement, the president urged all senators to support his measure and "oppose any legislation that fails to fulfill these four pillars -- that includes opposing any short-term 'Band-Aid' approach."
The remark brought action in the Senate to a standstill, with no votes on actual immigration legislation, despite assurances by leadership that an open-ended floor debate on the issue would take place this week, with both sides invited to offer amendments.
"Here we are on Wednesday, and we're off like a herd of turtles," sneered Republican Senator John Kennedy. "Nothing's happened."
Lawmakers for months have struggled to craft a compromise after Trump scrapped a program that allowed Dreamers to stay, and gave Congress until March 5 to find a solution.
Some 690,000 Dreamers registered under the Obama-era Deferred Action for Childhood Arrivals (DACA) program -- plus 1.1 million others who were eligible but did not sign up -- could begin to face deportation by that date if no fix is in place.
Top Republicans said Trump's plan has the best shot at becoming law out of those being considered.
But Democrats have panned it, making it highly unlikely that it would garner the 60 votes necessary to advance in the 100-member chamber.
- 'Growing consensus' -
A compromise was emerging from a bipartisan group nicknamed the "common sense coalition," which appeared set to release the text later Wednesday.
"We're making real progress," Republican Senator Susan Collins tweeted after hosting coalition members in her office.
Republican Senator Lindsey Graham said there was "growing consensus" around the plan, a narrower bill that would legalize 1.8 million Dreamers and provide $25 billion for border security including funding for a wall on the US-Mexico border, a long-held Trump priority.
"I think that's got the best chance of getting 60" votes, Graham told AFP.
With just three weeks before DACA recipients face possible deportation, young immigrants in Santa Monica, California used the occasion of Valentine's Day to conduct a "Vote for Love" outreach effort by imploring people to call senators' offices and urge them to back legislation that protects Dreamers.
In the midst of the showdown, Democrats stressed Trump would be to blame for any failure to reach a deal.
Americans "know this president not only created the problem, but seems to be against every solution that might pass because it isn't 100 percent of what he wants," top Senate Democrat Chuck Schumer said.
"If, at the end of the week, we are unable to find a bill that can pass... the responsibility will fall entirely on the president's shoulders and those in this body who went along with him."
A handful of Senate Republicans have said they would consider voting for the Collins compromise if the text is reasonable.
But number two Senate Republican John Cornyn said it was critical to pass legislation that could clear the House, where conservatives bridle at the thought of providing "amnesty" to millions of immigrants, and pass muster with Trump.
"The White House has been pretty adamant, and we agree, that the president's proposal will be the final deal," Cornyn told reporters.
With two legislative days remaining in the week, the path forward has narrowed dramatically.
"We're going to run out of time," Cornyn said, "and I'm kind of at a loss."
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)