Thousands of subway workers in Seoul and three other major cities are on strike after union workers and management failed to work out a compromise regarding the five-day workweek system.

The walkout, which began early Wednesday in Seoul, Daegu, Busan, and Incheon, has prompted Seoul city officials to mobilize non-union workers to minimize public inconvenience.

Union workers are demanding the additional employment of some 6,000 workers in order to implement the five-day workweek without any deterioration of present working conditions.

The management, on the other hand, is insisting that the current number of employees is sufficient to carry out a five-day working week. The five-day workweek system took effect at the beginning of the month.