WASHINGTON — His style was different, but the message was the same.

Two weeks after being sworn in, Federal Reserve Chairman Ben Bernanke yesterday made his first appearance before Congress, and in a straightforward manner, said the U.S. expansion was so strong that the central bank might need to raise interest rates again to control inflation.

During three hours of questions from the House Financial Services Committee, Bernanke displayed hardly a hint of nerves. Parrying questions on issues from healthcare to banking regulation, he managed to be concise, detailed and deferential.

"He had anticipated every question. And he knew how to answer them without ruffling any feathers," says Lyle Gramley, a former Fed governor who is now a senior economic adviser at Stanford Washington Research Group.

Bernanke's unadorned style quickly set him apart from his predecessor, Alan Greenspan, renowned for his opaque speech.

"We can actually understand your answers," said Rep. Scott Garrett, R-N.J., during the generally cordial hearing.

Presenting the Fed's twice-annual economic outlook, Bernanke, 52, told the committee that "the economic expansion remains on track." But he added that the economy could expand too quickly, exerting "further upward pressure on inflation" unless interest rates rose.

Looking ahead, he said that as the Fed makes "ongoing, provisional judgments about the risk to both inflation and growth," interest rate decisions will be more dependent on current data about the economy.

Wearing an understated gray suit and tie, and crossing his arms almost casually on the witness table, Bernanke also sought to reassure lawmakers and investors that he did not plan to enact major changes in the Fed's approach to policy. He said the strategy of Greenspan, who led the Fed for 18 1/2 years using a combination of formal models, anecdotal information and risk-management analysis, worked well.

"My intention is to maintain continuity," he said.

Stock markets seesawed as investors tried to digest Ber-nanke's comments. The Dow Jones industrial average ended the day up 30.58 points to 11,058.97.

Investors who bet on future Fed decisions in financial markets are fully pricing in a quarter-percentage-point increase in interest rates when Fed policymakers meet March 28, according to Daniel Jester, an economist at Moody's Economy.com. Investors increased the odds on a rate increase at the following meeting May 10 after hearing Bernanke speak.

"From the tone of his testimony today, it's obvious he sees a pretty strong economy," Jester said.

Fed policymakers have raised their target for short-term interest rates, which influence borrowing costs across the economy, to 4.5 percent, the highest in nearly five years. The Fed has raised rates slowly, in a series of 14 quarter-percentage-point increases starting in June 2004, when they were at a four-decade low.

Recent data suggest that a slowing in the economy in the fourth quarter was more a pause than the beginning of a longer-term trend.

Yesterday, the Fed said manufacturing activity expanded 0.7 percent in January after a 0.5 percent gain in December, while earlier in the week, the government said retail sales rose at the fastest pace in more than four years last month. The 4.7 percent jobless rate in January was the lowest since mid-2001.

Bernanke did lay out potential trouble spots, citing "significant uncertainty" about the path of home prices and construction.

But "at this point, a leveling out or a modest softening of housing activity seems more likely than a sharp contraction," he said.

He warned that high energy prices and tight supplies were likely to cause continued turbulence in the next several years and cautioned that the enormous U.S. trade deficit could not continue indefinitely.

He said Congress has to address unprecedented budget deficits expected as the baby boomers retire, straining Social Security and Medicare.

In another break from Green-span, Bernanke generally refrained from answering specific questions about tax, spending and other federal policies. "I think that in my role as the head of the central bank that I should not be involved in making specific recommendations about your internal decision-making process," Bernanke said.

Bill Hornbarger, fixed-income strategist at A.G. Edwards, said the markets took well to the testimony, grading the performance a "solid B+" and noting that "Bernanke seems like a guy you can have a cup of coffee with and have a conversation with. Greenspan was a little bit less approachable."

For a hearing that had been eagerly anticipated in the financial markets, the atmosphere in the room was generally low-key, with several empty seats. A nearby press room was crammed with reporters, however, filing stories while watching the hearing on television.

Bernanke, a former economics professor, White House economic adviser and Fed governor, seemed unfazed by the gaggle of photographers perched on the floor in front of the witness table.

"You should correct me if I'm mistaken," he said at one point, in un-Greenspan-like fashion.

Bernanke got only one question, late in the hearing, about his support for inflation targeting, a policy under which central banks set an explicit range for allowable inflation. Bernanke said he won't implement such a policy, which the Fed now follows informally, without consensus.