The head of South Korea's major TV broadcaster MBC vowed Friday to deal sternly with unionists waging an "illegal strike" and demanding his resignation.

MBC's unionized reporters and TV producers began an indefinite general strike on Jan. 30, demanding Kim Jae-cheul, the president and chief executive of the broadcaster, step down over what they call biased coverage of major social and political issues.

The walkout is affecting nearly all news and entertainment programs at the station, with the exception of dramas and programs whose production is outsourced.

"It is nonsense that they demand the resignation of a president chosen through legitimate procedures," Kim said during a meeting of senior company officials.

Kim, who showed up at the MBC offic for the first time in about three weeks, said he had been working off-site "to avoid unnecessary clashes" with unionists but had reached the limit of his patience.

"I will respond to the illegal strike sternly and according to (law and) principles," he said, vowing to take all possible measures, including legal action if necessary, to normalize the company.

In addition, management ordered all employees participating in the strike to return to work by 9 a.m. Monday or face disciplinary measures.

The union refused to back down, however, vowing to continue its strike until the company moves toward "fair journalism."

"We launched this strike because MBC has biased broadcasting,"

Jeong Yeong-ha, chief of the union, said. "We will continue the strike as scheduled until our broadcasting environment turns fair,"

he added.

The unionists argue that the broadcaster has intentionally omitted or reduced the coverage of politically sensitive issues, including rallies against the country's free trade agreement with the United States and suspicions surrounding President Lee Myung-bak's recent purchase of land for his retirement home in southern Seoul. (Yonhap News)