WASHINGTON, April 10 (Reuters) - The U.S. federal government reported that the March budget deficit rose $4 billion or 2% to $164 billion from a year ago as new individual and corporate tax breaks pushed refunds sharply higher, while relief payments to farmers also grew, the U.S. Treasury said on Friday.

The monthly budget data did not show a major increase in spending on the Iran war, with military and defense program outlays rising just $2 billion or 3% to $65 billion during the conflict's first month.

A Treasury official said that many war-related outlays, such as for replenishing weapons inventories, would come in later months.

Customs duty collections also softened in the month following the U.S. Supreme Court's annulment of President Donald Trump's broadest global tariffs imposed under an emergency law.

Customs receipts totaled $22.2 billion in March, down from $26.6 billion in February and monthly totals in the low $30 billion range late last year, but up from $8.2 billion in March 2025.

March receipts totaled $385 billion, up $17 billion or 5% from March 2025, while outlays totaled $549 billion, up $21 billion, or 4% from a year earlier.

After accounting for calendar-related adjustments of benefit payments, the March deficit would have been $250 billion, up $9 billion or 4% from March 2025.