Sales at U.S. retailers posted their smallest gain in nine months in April as high food and gasoline prices drew spending away from other areas, but upward revisions to March's data suggested consumer spending in the first quarter might have been stronger than initially thought.

Total retail sales increased 0.5 percent for a 10th straight month of gains, the Commerce Department said on Thursday. March sales were revised up to a 0.9 percent increase from a previously 0.4 percent rise.

Economists polled by Reuters had expected retail sales to increase 0.6 percent last month.

The data implied consumer spending, which accounts for 70 percent of U.S. economic activity, got off to slow start in the second quarter as household budgets remained stretched by high food and energy prices.

Consumer spending grew at a 2.7 percent rate in the first three months of 2011, braking from a 4.0 percent pace in the October-December period, according to the Commerce Department's first estimate of GDP released last month.

Receipts at gasoline stations, which accounted for about 10.5 percent of overall retail sales in April, rose 2.7 percent after rising 4.1 percent the prior month.

Gasoline prices rose 24 cents or 6.6 percent to $3.85 a gallon in April from March, according to the Energy Information Administration.

Excluding gasoline, retail sales were up 0.2 percent after rising 0.5 percent in March. Sales at food and beverage stores rose 1.2 percent after gaining 0.2 percent in March.

In the 12 months to April, overall sales were up 7.6 percent.

Sales excluding autos rose 0.6 percent last month, building on a 1.2 percent gain in March and in line with economists' expectations.

Auto sales rose 0.2 percent after declining 0.7 percent in March. Clothing store receipts rose 0.3 percent last month, while sales at building materials and garden equipment suppliers edged up 0.1 percent. So-called core retail sales -- which exclude autos, gasoline and building materials - rose 0.2 percent after a 0.6 percent rise in March.

Core sales correspond most closely with the consumer spending component of the government's gross domestic product report. Receipts at sporting goods, hobby, book and music stores fell 1.9 percent, the largest decline since November 2009. (Reporting by Lucia Mutikani, Editing by Andrea Ricci)