Washington — Dozens of public transit projects around the country are in danger of stalling as the White House's plan to boost U.S. infrastructure fails to gain momentum — with thousands of jobs at risk.

The uncertainty over these projects has worsened in recent days as President Donald Trump — who had vowed to make the week's focus infrastructure - faced a series of distractions, including a congressional hearing featuring former FBI director James Comey.

The president, who had called for $1 trillion in new infrastructure programs to create millions of jobs, now faces an increasing probability that not only will his proposal fail in Congress, but also that existing infrastructure efforts will stumble.

The situation has emerged because the Trump administration has signaled it wants to take an approach to infrastructure spending that is different from the previous administration's. Instead of funding many of the existing projects that depend on federal money — a practice that officials say they worry is wasteful — the administration says it wants to move toward a version of financing projects that is based far more on private funding.

The sudden uncertainty has left local officials who had long anticipated federal support for their projects worrying whether they will get it.

In previously unreported letters, officials at the Department of Transportation last week told project managers for a bus corridor in Pittsburgh and rail projects in Phoenix and New York that the administration's budget plan for next year "proposes no funding for new projects" under an existing federal program known as the Capital Investment Grant.

Robert Rubinstein, who received the letter as executive director of the Urban Redevelopment Authority of Pittsburgh, said the proposed cancellation of funding would effectively kill the project, which has been in the works for 10 years. It would have created an electric-bus corridor between Pittsburgh and nearby Oakland, Pennsylvania.

"We don't have enough resources locally to undertake the larger project," Rubinstein said. He said officials had sought roughly $80 million in federal money to go toward the $224 million project. He said the several million dollars already spent on studies and engineering reviews could be lost.

CIG funding allocates $2.3 billion each year to various projects and was recently authorized by lawmakers from both parties. Its projects include public transportation projects such as rail, streetcars, and rapid bus systems. The White House's most recent budget has proposed phasing out CIG funding, and the White House can block any new CIG projects even if there is congressional support.

Andrew Brady, senior director of government affairs at the American Public Transportation Association, said that more than 50 public transit projects are at risk of being denied federal funding because of Trump's planned cuts to infrastructure spending.

"He's saying a lot of good things on infrastructure, but what he's done is implement very real cuts to infrastructure programs," Brady said.

Capitol Hill aides closely tracking infrastructure funding say that uncertainty over the administration's infrastructure plans is particularly threatening to programs that are far along and are dependent on federal funding for completion.

The projects that are most at risk, they said, include some that have moved through the funding pipeline for years but are just short of final approval. Many are in states that Trump won last year, and they include a light-rail platform-lengthening project in Texas, a streetcar line in Arizona, and a bus rapid-transit line in Indiana.

Bryan Luellen, a spokesman for IndyGo, said the agency is concerned about long-term funding stability as it embarks on a major expansion of its system. The agency is expecting the CIG program to cover $75 million of the $96 million project and plans to seek federal funding for two other rapid transit projects in coming years.

"Obviously, the less federal support we have, the less we can do overall," he said.

Besides the transit program, Trump's budget proposes ending the Transportation Department's TIGER grant program, which was created under the Obama administration in the 2009 stimulus bill and has since funded $5 billion worth of road, rail, port and bicycle projects.

Trump's budget request said the program funds "projects with localized benefits" that often "do not rise to the level of national or regional significance."

Those projects, it said, would be better funded through another DOT grant program, Nationally Significant Freight and Highway Projects, that is focused on roads and freight rail.

Speaking at the Department of Transportation on Friday, Trump focused on his efforts to dismantle regulations that he says stand in the way of new building.

"The excruciating wait time for permitting has inflicted enormous financial pain to cities and states all throughout our nation and has blocked many important projects from ever getting off the ground," Trump said. "Many, many projects are long gone because they couldn't get permits and there was no reason for it."

Trump had originally held out hope that infrastructure spending could be a rare source of bipartisan action this year, given Democrats' support over time for the policy. But those hopes have dissipated in recent months as controversies enveloped the White House and Democrats grew skeptical of Trump's plans to provide large tax credits to private companies to finance much of the construction.

"We offered to work together. We offered our own infrastructure plan to the [White House] to spark discussion. Months passed. We heard nothing back," Senate Minority Leader Charles Schumer, D-N.Y., tweeted Friday. "Now the few details we have of [Trump's] plan show it's private-sector driven, has minimal investment & ignores huge sectors of infrastructure."

White House officials have said they are undertaking an expansive review of infrastructure spending but argue that, in the meantime, any promise of federal spending could delay projects as local officials await word. The White House has proposed spending just $5 billion toward its $1 trillion infrastructure project next year.

In a statement, White House assistant press secretary Natalie Strom said of the CIG program in particular that "there's always been a great deal of uncertainty around the funding of that program and as a matter of fact uncertainty is one of the most significant impediments to infrastructure, whether it's funded by the public or private sector."

"That's why the President is committed to simplifying and streamlining the process so that there is less uncertainty all around," she said.

Trump was supposed to spend all this week promoting his infrastructure package, but he and top aides have been beset by distractions, staffing shortages and confusion over where money for the infrastructure program would originate.

Trump has suggested that the entire $1 trillion might come from the federal government, but aides have recently said $200 billion would come from the federal government and $800 billion from private investors, states and cities.

"My feeling is unless you have a pretty serious broad-based debate about funding, you're never going to get to the numbers that the president has talked about," said Ray LaHood, a former Republican congressman who served as transportation secretary for President Barack Obama.

So far, Trump's advisers have publicly identified projects to cut at a faster pace than they've identified projects to fund, leading to widespread confusion about the administration's intent.

Dan Slane, an Ohio developer who worked on the infrastructure plan during Trump's transition, said he is still receiving calls from state and local governments, frustrated with the slow pace of planning and asking him for details.

"They don't want to pay for anything," Slane said of the administration. "They want all infrastructure to be privately financed or privately owned."

White House officials say they are taking their time because they want to create more accountability for how money is spent.

Trump also went this week to Cincinnati to tout his infrastructure plans, but it quickly became apparent how difficult it would be for the White House to stay focused on infrastructure alone.

"If there's not something out there for the Congress to really look at by the fall, we may have wasted a lot a time," LaHood said.