Workers of the Hyundai conglomerate held a board chairman and plant executives captive for a fourth day and launched a strike Monday in protests for higher wages.

A spokesman of Hyundai Precision Industry Co. at Changwon, 195 miles southeast of Seoul, said workers were holding board chairman Chung Mon-gu and 10 other executives for the fourth day demanding a 40 percent wage increase.The spokesman said Chung, 51, was suffering from poor health, but union members refused to let him come out of his office in the plant unless he accepted the labor demand.

Some 20,000 workers at Hyundai Motor Co. also started a strike demanding a $184 per month increase at the company's plant in Ulsan, a spokesman for the Hyundai Group said. Hyundai Motor is South Korea's largest automaker and exports low-priced compacts to the United States.