President Donald Trump unveiled a $4.746 trillion federal budget proposal for fiscal 2020 that projects annual U.S. deficits exceeding $1 trillion at least through fiscal 2022 and gradually slowing economic growth for the next several years.

Under the proposed budget plan, the fiscal deficit is expected to widen to $1.092 trillion in fiscal 2019, which ends Sept. 30, and to $1.101 trillion in fiscal 2020. The shortfall is expected to narrow to $1.068 trillion in fiscal 2021 and to $1.049 trillion in fiscal 2022, before shrinking and staying below $1 trillion each subsequent year through 2029.

The White House said proposals in the latest fiscal plan would put the U.S. "on track" to reach budget balance by 2034.

"This budget shows that we can return to fiscal sanity without halting our economic resurgence while continuing to invest in critical priorities," said Russell Vought, acting director of the White House Office of Management and Budget.

The budget forecasts include an assumption that the U.S. economy will grow by 3.2% in 2019 before slowing to a 3.1% expansion in 2020, 3.0% growth until 2024 and then below 3.0% through 2029.

Vought said the proposed 2020 budget "will balance in 15 years, end runaway spending, and secure prosperity for future generations."

The budget plan includes $2.7 trillion in proposed spending cuts, which is higher than in any previous administration, following Trump's directive to reduce nondefense spending by 5%, according to the White House.

Vought has told CNBC that the fiscal 2020 budget calls for $8.6 billion to build barriers on the U.S.-Mexico border, higher than Trump's previous funding demand of $5.7 billion that triggered a partial government shutdown from December 2018 to January.

In a statement, House Speaker Nancy Pelosi, D-Calif., said Congress will reject Trump's "toxic, destructive budget request," calling the proposed spending cuts "a roadmap to a sicker, weaker America."