New claims for U.S. unemployment benefits fell last week to a four-year low, another sign that the country's labor market is strengthening.

The government reported Thursday that 348,000 workers made first-time applications for assistance last week, down 5,000 from the previous week. It was the lowest total since February 2008.

U.S. companies have been dismissing fewer workers in recent months. At the same time, from December to February, an average of nearly a quarter million jobs were added each month to payrolls.

Even as the number of new layoffs has waned, long-term unemployment remains a problem in the U.S. as the world's largest economy recovers from the recession that was its worst in seven decades. Nearly 13 million workers are still unemployed, with more than 40 percent of them jobless for six months or more.

The U.S. jobless rate was pegged at 8.3 percent in both January and February, and had been falling in the last half of 2011. The rate is now the same as in February 2009, the first full month in office for U.S. President Barack Obama. But it is elevated by U.S. historical standards, with a 5 percent figure more common.

Mr. Obama's handling of the U.S. economy has become a focal point of the U.S. presidential election campaign as the Democrat seeks a second four-year term in November's national election.

He has touted the job growth and noted that U.S. manufacturers are adding workers again for the first time in years. But the leading Republican contender seeking to oust him, former venture capitalist Mitt Romney, says he knows how to boost the American economy at a faster pace, with less government regulation and lower taxes.