Union workers at GM Korea Co., the South Korean unit of U.S. automaker General Motors Co., staged a partial strike on Tuesday after wage negotiations with management broke down, the carmaker said.

   Unionized employees at the company's Incheon, Gunsan and Changwon factories stopped work for about three hours from 1:50 p.m., after holding a similar work stoppage the previous day, GM Korea said.

   GM Korea's union said assembly line workers will not report for extra night shift duties, and work will be stopped again for three hours on Wednesday.

   The car maker's management and union have held 12 rounds of negotiations since May 25 to try to iron out differences in pay hikes.

   The union is calling for a 150,611 won (US$141.40) increase in monthly base pay and a bonus equal to 30 percent of last year's net profits. Management has countered with a monthly pay increase of 68,828 won and a bonus of 2.2 million won.

   If employees follow through with the three-day partial walkout, it could disrupt the production of 3,600 vehicles, the company said.

   GM Korea, meanwhile, said it has not been able to set a date for the next round of talks with union leaders, but said that every effort will be made to resolve outstanding differences as soon as possible. (Yonhap News)