The U.S. Commerce Department released the retail sales data on Wednesday. The U.S. retail sales were flat in April, missing expectations for a 0.2% increase, after a 1.1% gain in March. March's figure was revised up from a 0.9% increase.

The reading was driven by lower automobiles and gasoline purchases. Automobiles sales decreased 0.4% in April, while gasoline station sales decreased 0.7%.

Retail sales excluding automobiles increased 0.1% in April, missing forecasts for a 0.5% rise, after a 0.7% gain in March. March's figure was revised up from a 0.4% rise.

Sales at clothing retailers climbed 0.2%. Sales at building material and garden equipment stores were up 0.3% and sales at restaurants and bars increased 0.7%.

Sales at electronics and appliance outlets were down 0.4% in April, whiles sales at online stores gained 0.8%.

These figures are adding to concerns that U.S. economy is losing momentum, and the Fed might delay its first interest rate hike.