The number of mass layoffs by U.S. employers rose by 533 in August from July, with the manufacturing sector the hardest hit, Labor Department data showed on Wednesday.

The number of mass layoff actions -- defined as job cuts involving at least 50 people from a single employer -- rose to 2,690 last month, affecting 259,307 workers. That brought the total of mass layoffs so far this year to 21,184.

A total of 279 mass layoff events were reported in the manufacturing sector in August, the department said.

While the broader economy appears to be recovering from its deepest and longest recession in 70 years, unemployment continues to rise. There are fears rising joblessness could hamper the recovery.

The U.S. unemployment rate hit a 26-year high of 9.7 percent in August, and many economists expect it to peak above 10 percent early next year.

In the 21 months since the start of the recession, the total number of mass layoff events was 44,669, accounting for over 4.56 million jobs, the department said.

Unemployment Manufacturing