U.S. retail sales recorded their biggest drop in more than a year in May amid declining purchases of motor vehicles and discretionary spending, which could temper expectations for a sharp acceleration in economic growth in the second quarter.

The Commerce Department said on Wednesday retail sales fell 0.3 percent last month after an unrevised 0.4 percent increase in April. May's decline was the largest since January 2016 and confounded economists' expectation for a 0.1 percent gain.

Retail sales rose 3.8 percent in May on a year-on-year basis. Some of the drop in monthly retail sales reflected lower gasoline prices, which weighed on receipts at service stations.

Excluding automobiles, gasoline, building materials and food services, retail sales were unchanged last month after an upwardly revised 0.6 percent rise in April.

These so-called core retail sales correspond most closely with the consumer spending component of gross domestic product and were previously reported to have increased 0.2 percent in April.

Growth is expected to pick up this quarter after being held back by a near stall in consumer spending and a slower pace of inventory investment at the start of the year.