The chief of the U.S. central bank says American consumers have been “exceptionally cautious” in their spending habits in recent months, one reason that the country’s economy is growing at a tepid pace.

Federal Reserve Chairman Ben Bernanke said Thursday that spending by U.S. households expanded moderately in 2010, but diminished this year in the face of higher gas prices, persistently high unemployment and large personal debts. But he said that even with such financial pressures, household spending has shown “unusual weakness.”

Weak consumer spending significantly affects the U.S. economy, because household purchases normally account for 70 percent of the country’s economic output.

Bernanke spoke to economic leaders in Minneapolis, Minnesota. He renewed his recent pledge that the central bank at its meeting later this month “will certainly do all that it can” to boost the sluggish economy and job growth without increasing consumer prices. But he gave no details on how the bank might act.

Earlier, the U.S. reported that the number of unemployed workers seeking new government financial assistance edged up last week, more evidence that the country’s economy is slowing.

The government said 414,000 jobless workers sought their first unemployment compensation, 2,000 more than the previous week. The number of claims suggested that U.S. employers are not laying off significantly more workers, but not hiring more either.

The weekly report came as President Barack Obama prepared to present his plan for job growth to a joint session of Congress Thursday night. Officials say his plan will call for an extension of jobless benefits for workers who have been unemployed for extended periods, tax incentives for companies to hire more workers and funding for construction projects to fix the country’s deteriorating roads and schools.

Another government report Thursday presented a more favorable picture for the country’s lagging economy. The U.S. said its trade deficit fell sharply in July, dropping more than 13 percent from June to about $45 billion. That may indicate that American manufacturers might be able to sustain weaker demand for their products within the U.S. with more sales overseas.

Exports increased to $178 billion, with the shipment of capital goods, autos and parts to customers overseas the highest on record.