U.S. retailers warned of rising costs and cautious consumers even as a late Easter boosted sales of clothing and other holiday-related items in April, helping many beat sales expectations.

Gasoline pushing above $4 a gallon and a slow recovery in the job market are also likely to weigh on sales for the next several months, with no major events to spur shopping until the key back to school season, analysts said.

The consumer has been resilient throughout with spending, said Ken Perkins, president of research firm Retail Metrics. I don't see a catalyst between now and back to school, though.

Same-store sales rose 8.9 percent at the 25 retailers tracked by Thomson Reuters, compared with expectations for an 8.2 percent increase. (For a related graphic, click http://r.reuters.com/puq39r)

Clothing retailer Gap Inc , for example, posted an 8 percent increase in sales at stores open at least a year in April, surprising analysts who, on average, had expected a 0.8 percent drop.

At the same time, the company also forecast earnings for the April quarter below analysts' expectations and said merchandise margins were down significantly, with raw materials costs rising more than it expected.

Rising costs are pressuring clothing manufacturers, which are trying to pass some of them on to consumers who may not be willing to pay more for items that do not stand out.

If you don't have differentiated product, and that's one of the big issues that the Gap has at some point, you have pressure on the margin front, Perkins said.

GOOD FOR SOME

Still, some retailers, including Victoria's Secret parent Limited Brands Inc , raised their quarterly earnings forecasts.

The biggest factor boosting sales is Easter, which was on April 24 this year. Last year's holiday, on April 4, moved many holiday-related purchases into March.

Gasoline also helped sales at retailers that sold the fuel, but rising prices for it are likely to weigh on discretionary purchases this summer.

I paid $4.45 a gallon today, Patty Edwards, chief investment officer at Bellevue, Washington-based Trutina Financial, said on Wednesday. I'll tell you, that is certainly cutting into my Nordstrom fund.

Upscale retailer Nordstrom posted a 7.6 percent increase in April same-store sales, below the 8.1 percent rise analysts were expecting.

Cooler weather than last year might also have hurt sales, according to business weather advisory firm Planalytics.

Target Corp's same-store sales were up 13.1 percent, just below analysts' expectations.

Guests continued to be very cautious in their spending leading up to Easter, said Target CEO Gregg Steinhafel.

Department-store operator Macy's had a 10.8 percent increase, above the 8.1 percent gain analysts expected.

Sales of gasoline helped Costco Wholesale Corp beat estimates, although selling more of it also cuts into the retailer's margins.

But Costco also showed the inflation pressures that are weighing on consumers, not only in higher prices for gasoline, but also for groceries as food companies pass on increased costs of ingredients and transportation.

Fresh food prices were up mid-to-high single digits, for example, the company said.

Costco had the type of April sales performance that captured the very essence of the news flow that dominated during the month: inflation, weak dollar, and a slightly more guarded U.S. consumer, Wall Street Strategies analyst Brian Sozzi said in a research note.

Limited Brands blew through expectations with a 20 percent increase in April sales, compared with the analysts' average estimate of 12.2 percent.

The company, which also owns Bath and Body Works, raised its quarterly earnings outlook to a range of 37 to 39 cents a share, excluding items. It had previously expected 26 cents to 31 cents, and analysts had forecast 36 cents.

Stocks have priced in a strong performance in April, with the Standard & Poor's retail index <.RLX> up 15.9 percent since March sales were reported, compared with a 13.6 percent increase in the S&P 500 <.SPX>.

(Reporting by Brad Dorfman, editing by Bernard Orr and Lisa Von Ahn)

Easter Inflation