Chuck Hagel, US Secretary of Defense, testifies before the US Senate Budget Committee about US President Barrack Obama's proposed budget request for fiscal year 2014 for defense, on Capitol Hill in Washington DC, capital of the United States, June 12, 2013.[Photo/Xinhua]

WASHINGTON - US federal government recorded a budget deficit of $138.7 billion in May, US Treasury Department figures revealed Wednesday.

The monthly budget deficit was highest since February, after the federal government registered a $112.9 billion in budget surplus in April.

The federal government raked in a revenue of $197.2 billion in May, and reported outlays of $335.9 billion in the same month.

The budget gap for the first eight months of the current fiscal year starting in October last year totaled $626.3 billion.

Due to the ballooning entitlement spending, waning government revenue, as well as massive spending on wars in Iraq and Afghanistan, the US federal government's budget deficit has surpassed $1 trillion for four consecutive years under President Barack Obama's watch.