By Tom Doggett and Emily Stephenson

WASHINGTON (Reuters) - Senators hoping to rein in high oil and gasoline prices slammed the futures market regulator on Thursday for not moving faster to crack down on out-of-control speculators in commodity markets.

At a meeting with lawmakers on Capitol Hill, Commodity Futures Trading Commission Chairman Gary Gensler refused to spell out when the agency would act on a rule to limit the number of contracts big market players can hold in oil and other commodities.

"There is nothing that I heard from him which suggests any sense of urgency about the need to protect consumers or in fact to protect our economy," Senator Bernie Sanders told reporters after he and five other senators met with Gensler.

Sanders, an Independent from Vermont, said the CFTC violated the law when it failed to impose position limits on energy and other commodities by January, as required under the Dodd-Frank financial reform law.

"The chief regulator on oil speculation, in my view, is breaking the law," he said.

Senator Maria Cantwell, a Democrat from Washington state, said the CFTC needed to act now to drive out the excessive speculation in the market.

She said Gensler told the senators that speculators made up about 80 percent of trading in the energy market, and the other 20 percent were legitimate hedgers trying to protect against swings in prices or supply.

"What it tells us is there should be even more urgency to act. It is imperative that the CFTC take an aggressive role and protect consumers today," Cantwell said.

She said if the CFTC does not act, Congress would look for ways to force the agency to take action. Such a move would be difficult as many Republicans have problems with the financial reform law.

With nearly $4 a gallon gasoline prices hindering U.S. economic recovery, a group of 17 U.S. senators called on the CFTC two weeks ago to unveil its final plan by May 23. The agency made an initial proposal for the rules earlier this year, but has not set a vote to finalize them.

Democratic Senator Ron Wyden of Oregon criticized the CFTC for not zeroing in on position limits for oil, which he said was more important than the other 27 commodities the agency is considering for limits.

"It is not cocoa that is driving the American economy right now. I don't have my phone ringing off the hook on cocoa. It is oil that drives the economy, and we are looking for some significantly more aggressive action," he said.

Gensler's meeting with the senators followed an oil manipulation lawsuit filed by the agency this week against two traders and a global trading house owned by Norwegian billionaire John Fredriksen.

Sanders said he was concerned the CFTC may wait three years to go after any manipulating firms or traders who may be behind the current high energy prices.

"What the American people want is action now," he said.

Gensler has said the commission will begin considering several rulemakings in late summer and he wanted position limits to be in that first batch.

"It's time to get this rule done," Senator Amy Klobuchar, a Democrat from Minnesota, told reporters as she left the meeting.

Gensler did not take questions after the meeting, as reporters tried to keep up with his quick pace down a long hallway of the Dirksen Senate Office Building, where the meeting took place.

A long-simmering debate over the role of speculators in commodity markets has been revived this year as many prices push toward their 2008 peaks.

While critics say that investors with no intention of holding real oil or metals or grains are artificially driving up prices, many analysts argue that tight market fundamentals fully explain the latest run-up in prices.

John Felmy, the chief economist for the American Petroleum Institute, told reporters on Thursday that high oil prices reflect tighter global supplies and strong demand, and speculators should not be blamed.

(Reporting by Tom Doggett, editing by Jonathan Leff, David Gregorio and Lisa Shumaker)