NEW YORK - Exxon Mobil Corp. kicked off 2007 with a 10 percent increase in profit, its best-ever first quarter, as higher margins on oil refining and chemical operations offset lower prices for crude oil and natural gas.

Exxon Mobil, the world's largest publicly traded oil company, said yesterday that it earned $9.3 billion in the January-March period, beating Wall Street expectations, even as revenue slipped to well short of analysts' forecasts.

Also yesterday, Valero Energy Corp., the nation's largest independent oil refiner, said its first-quarter profit jumped 35 percent because of stronger gasoline and distillate margins.

The market price for crude oil was off more than $5 a barrel in the first quarter from a year ago. The comparable price for natural gas also was down.

Still, given the rise in gasoline prices at the pump in recent weeks, oil majors such as Exxon Mobil were getting little sympathy from U.S. consumers for not earning as much as they could have if market prices for their products had been higher to start 2007.

"They're hurting me all the way around," Bill LoGerfo of Staten Island, N.Y., said yesterday as he paid $3.27 a gallon for premium unleaded to fill up his car at a BP station in Manhattan. Regular unleaded was selling for $3.03 a gallon.

"I'm in the construction business, so it makes it more expensive to get materials shipped to me," LoGerfo said. "These prices really trickle down to the little guy."

In response to the new round of oil profits, Sen. Bob Casey (D., Pa.) introduced legislation yesterday that he hoped would curtail rising gas prices. Casey's bill would impose a windfall-profits tax, close certain tax loopholes for big oil companies, and use the money for research into biofuels and other related projects.

Investors, however, pushed Exxon Mobil shares up 63 cents to a 52-week high of $80.55 on the New York Stock Exchange.

Exxon Mobil's profit amounted to $1.62 a share, up from $1.37 a share, or $8.4 billion, a year ago. Analysts polled by Thomson Financial were looking for a profit of $1.52 a share.

Revenue fell to $87.2 billion from $88.9 billion a year earlier, well below the $100 billion analysts had forecast.

Last year, the company posted the largest annual profit by a U.S. company: $39.5 billion. That result topped the previous record, also by Exxon Mobil, of $36.13 billion set in 2005.

Last month, Exxon Mobil said it would spend some of that money on more than 20 new global projects in the next three years, investments expected to add one million oil-equivalent barrels a day to its volumes at peak production.

The company said it spent $4.3 billion on capital and exploration projects in the first quarter, and planned to spend roughly $20 billion this year on such projects.