U.S. firms planned the highest number of layoffs in June since January 2004, led by the automotive and retail industries, employment consulting firm Challenger, Gray & Christmas Inc. (search) said on Wednesday.

Challenger, Gray & Christmas said employers announced 110,996 job cuts last month, up from 82,283 in May, and 73 percent higher than June 2004.

"The cuts are not necessarily an indication of economic weakness, but rather the by-product of numerous trends, including changing consumer demand, outsourcing, mergers and acquisitions, automation and consolidation," said John A. Challenger (search), chief executive officer of Challenger, Gray & Christmas, in a report.

The report said job cuts have been rising in 2005 despite other report showing economic growth and job gains.

The data comes a few days before the government releases its non-farm payroll (search) data for June, which according to economists polled by Reuters, is expected to be 188,500.

"We are also starting to see job cuts resulting from higher health care costs as well as higher oil and natural gas prices," he said.