The number of newly laid-off workers filing claims for unemployment benefits shot up last week by the biggest amount in four months, the Associated Press reported.

The U.S. Labor Department reported a total of 317,000 applications for unemployment benefits last week, up 16,000 from the previous week. It was the biggest increase since jobless claims rose by 18,000 during the week of May 9.

The rise was larger than analysts had been expecting and could be a further sign that the labor market is slowing under the impact of the worst slump in housing in 16 years and a credit crunch that shook global markets in August.

Analysts believe the unemployment rate probably rose in September to 4.7 percent, up from 4.6 percent in August, although they are expecting that businesses added 100,000 jobs to their payrolls.

The unemployment report is being closely followed by Wall Street, where investors believe it will provide the key piece of data the Federal Reserve will need to decide whether to cut interest rates further.