The U.S. jobless rate edged lower in April, but the government said Friday that job growth in the world's largest economy was modest.

The Labor Department said the unemployment rate fell a tenth of a percentage point from March to 8.1 percent last month. But for the second straight month, more workers left the labor market and thus were not counted in the U.S. employment survey.

At the same time, employers added another 115,000 workers to their payrolls last month, but that was well below the 160,000 figure that economists had predicted. The April figure also fell below the 120,000 jobs added in March and signaled that corporations have markedly slowed their hiring. The American economy had added nearly 250,000 jobs a month early in the year.

The U.S. has recovered only slowly from its deep recession in 2008 and 2009, its worst downturn since the Great Depression of the 1930s.

The state of the U.S. economy has emerged as the dominant issue in the country's presidential election campaign, heading to the vote in November.

U.S. President Barack Obama, a Democrat, is running for another four-year term. While he remains personally popular, many voters have questioned his oversight of the nation's economy. Earlier in the year, he touted the labor market's robust job growth. But now job growth has tailed off sharply.

His presumptive Republican challenger, one-time venture capitalist Mitt Romney, has attacked Mr. Obama's White House tenure as a failed presidency, especially his handling of the economy. Romney has called for less government regulation of corporations and lower taxes to boost the economy.