WASHINGTON (Reuters) - The U.S. trade deficit widened sharply in September as businesses boosted imports to meet robust domestic demand and in anticipation of higher tariffs on goods.

The trade gap increased 19.2% to $84.4 billion from a revised $70.8 billion in August also as exports fell, the Commerce Department's Bureau of Economic Analysis said on Tuesday. Economists polled by Reuters had forecast the trade deficit swelling to $84.1 billion from the previously reported $70.4 billion in August.

Republican candidate Donald Trump has promised to impose a 60% tariff on Chinese goods and at least a 10% levy on all other imports if he wins Tuesday's presidential election. Trump is locked in a tight race for the White House with Vice President and Democratic Party nominee Kamala Harris.

Trade subtracted 0.56 percentage point from gross domestic product in the third quarter. It has been a drag on economic growth for three straight quarters. The economy grew at a 2.8% annualized rate in the July-September quarter.