This photo shows Seoul Station in the capital on Nov. 18, Monday, after the Korean Railway Workers' Union launched a work-to-rule protest. (Yonhap)

Railway workers launched a "work-to-rule" protest Monday, causing delays in subway services in the capital area, railway officials said.

The labor slowdown was launched by the Korean Railway Workers' Union to demand higher pay and a bigger workforce, with plans to begin an indefinite general strike early next month.

As of 8 a.m., trains were being delayed by between 5 and 20 minutes on capital area subway lines 1, 3 and 4 and the Suin-Bundang, Gyeongui-Central and Seohae lines, according to the Korea Railroad Corp. (KORAIL).

All regular trains and KTX high-speed trains were operating normally.

A KORAIL official said an emergency task force was set up the previous day to maintain a prompt response system and minimize passengers' inconvenience.

Any violations of company rules or the law by the striking workers will be handled strictly, the official said. (Yonhap)