(CNN) US deficits are expected to balloon to $1 trillion when official figures are released next week -- but Treasury Secretary Steven Mnuchin says the massive Republican tax cut won't be to blame.

Instead, Mnuchin said Democrats were at fault for pushing spending increases on health and education in exchange for military budget increases as part of a massive spending package President Donald Trump signed in September 2017.

"People are going to want to say the deficit is because of the tax cuts. That's not the real story," said Mnuchin in an interview Thursday with CNN. "The real story is we made a significant investment in the military which is very, very important, and to get that done we had to increase non-military spending."

To avert a government shutdown, Republicans and Democrats struck a deal last year that included raising the spending on other government programs.

"If we could have approved that with 51 votes instead of 60 votes, we would not have spent as much money on non-military spending and the budget deficit would have been considerably smaller," Mnuchin said on the sidelines of the annual International Monetary Fund conference in Bali, Indonesia.

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