The U.S. budget deficit widened to $310 billion in the first four months of the fiscal year, underscoring the revenue hit from Republican tax cuts and an increase in government spending.

The budget gap widened 77 percent compared with the same October-January period a year earlier, according to the Treasury monthly budget report released on Tuesday, which was delayed by the government shutdown.

Receipts fell by 2 percent to $1.1 trillion, while spending rose 9 percent to $1.4 trillion.

The budget received a bump in customs duties, which almost doubled to about $25 billion, reflecting the Trump administration’s tariffs on Chinese imports, steel and other goods.

The financial shortfall is set to widen further in the coming years as the Republican tax cut package, which costs about $1.5 trillion over a decade, and increased spending for defense and other priorities boost government outlays. Some policy makers and economists are flagging concern about the growing debt burden, saying it risks America’s credit quality among borrowers, while other economists see more room to run.

Tax receipts fell for both corporations and individuals, the Treasury data showed.

The Congressional Budget Office, a non-partisan federal agency, forecast earlier this year that the budget gap in the fiscal year through September would widen to $897 billion, up by $118 billion from a year earlier.

In January, the U.S. posted a budget surplus of $8.7 billion, the smallest gain for the month since a shortfall of $17.5 billion was recorded in 2015, according to Treasury data compiled by Bloomberg.