Gov. Pat Quinn has offered his support to workers striking outside a Caterpillar plant south of Chicago.

The Peoria-based heavy-equipment maker has been among the sharpest critics of Illinois' state government and the management of its economy. Last year, Caterpillar's chief executive pressed Quinn on the economy and reminded him that the company has out-of-state suitors.

The governor visited about 100 striking workers Friday at the Joliet plant and donated $10,000 toward a food fund to support them. The money came from his re-election campaign funds.

Quinn told the workers that "when people are united they can't be defeated."

The workers walked off the job May 1. Their union is demanding cost-of-living pay increases and lower health-care premiums, and is asking the company to honor seniority rights.