WASHINGTON (AP) — President Donald Trump is proposing a plan that provides a path to citizenship for 1.8 million of the so-called "Dreamer" immigrants, tighter restrictions on legal immigration and $25 billion in border security, the White House said, putting forward an outline likely to find resistance from some of Trump's conservative allies and deep opposition from immigration activists.

Senior White House officials offered a preview of Trump's immigration framework Thursday, casting it as a compromise that could pass the Senate. The proposal represents a reversal for the president, who once promised to eliminate an Obama-era program protecting immigrants brought to the U.S. as children and now in the country illegally. He later urged lawmakers to extend the program, but maintained he was not considering citizenship.

The Obama-era Deferred Action for Childhood Arrivals program currently covers roughly 690,000 of those younger immigrants — about half the number who qualify for the program, according to independent estimates. Trump's plan would expand this further by adjusting some of the requirements, officials said, but they would not offer specific details. It would not allow parents of those immigrants to seek lawful status, the officials said.

On Wednesday, Trump said he was open to a pathway to citizenship for the younger immigrants. "We're going to morph into it," Trump told reporters. "It's going to happen, at some point in the future, over a period of 10 to 12 years."

Recipients could have their legal status revoked due to criminal behavior or national security threats, the officials said, and eventual citizenship would require still-unspecified work and education requirements — and a finding that the immigrants are of "good moral character."

Trump ended the DACA program in September, setting a March 5 deadline for Congress to provide legal protections or the program's recipients would once again be subject to deportation. The officials said Trump would only sign legislation providing those protections if the other immigration changes he is proposing are implemented.

Trump's plan would only allow immigrants to sponsor their spouses and underage children to join them in the U.S., doing away with provisions allowing parents, adult siblings and others to enter the country. The officials said it would only end new applications for visas, allowing those already in the pipeline to be processed.

It would also end the diversity visa lottery program, which drew Trump's attention after the New York City truck attack last year, redirecting the allotment annually to bringing down the existing backlog in visa applications.

The officials spoke on the condition of anonymity because they were not authorized to publicly discuss the plan before its release.

Trump had previously ruled out the idea of citizenship for the Dreamers, saying in September: "We're not looking at citizenship. We're not looking at amnesty. We're looking at allowing people to stay here."

Trump earlier this month had deferred to a bipartisan, bicameral group of lawmakers to craft an immigration proposal, saying he would sign whatever they passed. But as talks on Capitol Hill broke down — in part because of controversy Trump ginned up using vulgar language to describe other countries — the White House decided to offer its own framework.

The release follows on concerns raised by Senate Majority Leader Mitch McConnell that the president had not sufficiently laid out his priorities. One official said the Thursday release represents a plan for the Senate, with the administration expecting a different bill to pass the House.

The nonpartisan Migration Policy Institute said it believes the largest share of the White House's 1.8 million people who'd be eligible for citizenship — 1.3 million — are people who currently meet all of DACA's eligibility requirements. These include years in the U.S., their ages now and when they entered this country, and whether they have a high school or equivalent education.

Another 400,000 are people who'd be eligible for DACA protection but for their education. And 100,000 more are people who are under age 15 —the minimum age allowed for most people requesting protection under the program.

Moderate Sen. Joe Manchin, D-W.Va., said he was "very encouraged" by Trump's surprising words, which the president made late Wednesday in impromptu comments to reporters.