(CNN) The Congressional Budget Office raised its estimate of the projected federal budget deficit Wednesday and is now predicting that the deficit will reach $960 billion for the 2019 fiscal year, which ends on September 30, and reach $1 trillion for the 2020 fiscal year.

The CBO had previously estimated a $896 billion deficit for 2019 and $892 billion for 2020.

The Treasury Department reported earlier this month that the US budget deficit has already hit $867 billion for the first 10 months of the fiscal year, an increase of 27% over this time last year.

"The nation's fiscal outlook is challenging," said Phill Swagel, director of the CBO. "Federal debt, which is already high by historical standards, is on an unstainable course, projected to rise even higher after 2029 because of the aging of the population, growth in per capita spending on health care and rising interest costs."

He added that to put spending on a sustainable course, "lawmakers will have to make significant changes to tax and spending policies -- making revenues larger than they would be under current law, reducing spending below projected amounts, or adopting some combination of those approaches."

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