NEW YORK (CNN/Money) - Retail sales rose at a solid clip in May, the government said Monday, boosted mainly by sales of cars and auto parts.

The Commerce Department reported that sales jumped 1.2 percent to a seasonally adjusted $335.8 billion last month, compared with a revised 0.6 percent decline in April.

Excluding autos -- which account for about a quarter of total sales and can fluctuate widely from month to month -- sales rose 0.7 percent to $257 billion from a revised 0.1 percent decline in April.

Economists, on average, had expected total sales to rise 1.0 percent and sales excluding autos to rise 0.4 percent, according to Briefing.com.

"The overall story is one of continued strength of the consumer but there are a couple of underlying stories here too," said Michael Niemira, chief economist and director of research with the International Council of Shopping Centers (ICSC).

"We did see a boost from gas prices, we're also coming off a big surge in building materials. So there were some big swings in some components of the report," Niemira said. "But broadly, even excluding the volatile cars component, the gain was 0.7 percent, which is still quite healthy."

Among the best-performing categories last month, sales of autos and auto parts rose 2.7 percent from a revised 2.1 decline in April . Sales at gas stations rose a robust 4.0 percent after rising a revised 0.3 percent in the prior month.

Sales at general merchandise stores rose 1.3 percent, compared with a revised 0.7 percent decline, while clothing sales rose 0.9 percent after a revised 2.3 percent decline the prior month.

However, sales of building materials and garden equipment fell 1.4 percent after a revised 0.4 percent dip the prior month. Consumers also pulled back from eating out last month. Sales at restaurants slipped 0.3 percent compared to a 0.2. percent decline the prior month.

"We haven't yet seen the negative effect of gas prices on consumer spending. It's certainly not here in these numbers. That doesn't mean it's not there. Certainly the weekly retail sales numbers have been sluggish," said Conference Board economist Delos Smith.

"Gas prices have come down a couple of pennies but are still above $2 a gallon," Smith said. "You can't have these higher levels at the pump and not see an economic impact down the road. "I think it's a matter of time before the numbers start to reflect some slowdown."