Four leaders of the state rail company‘s labor union were formally detained Friday to undergo further questioning for their alleged role in organizing what the government calls an illegal strike.

The leaders of the state-run Korea Railroad Corp. union, including the head Kim Myung-hwan, were put under detention immediately after a district court approved the prosecution’s request for arrest warrants.

“(Their) crimes have been ascertained enough, and there is a reasonable concern that they might try to flee or destroy evidence,” Judge Lee Dong-wook of the Seoul Western District Court said in issuing the warrant.

The court, however, dismissed the prosecution‘s request to issue warrants for five other union leaders.

Prosecutors alleged that the nine played leading roles in the strike that disrupted the national rail system for more than three weeks, the longest ever. The government claims that the strike caused huge financial losses.

The union leaders voluntarily turned themselves in to police Tuesday after defying police summons and taking refuge in several groups in different locations even after the strike ended on Dec. 30.

The union claimed its leaders had not been fleeing police and had only been discussing unresolved issues such as the management’s disciplinary measures against unionists who participated in the walkout.

Hundreds of KORAIL unionists face tough disciplinary measures for their participation in the strike, which protested a government plan to establish a subsidiary to run some high-speed train services. The union suspects the move is a precursor to rail privatization.

Despite a dramatic closure after rival parties cut a deal with the KORAIL union to form a parliamentary subcommittee on preventing the privatization of rail services, police and prosecutors have vowed no leniency toward those who led the walkout.

Following the arrests on Friday, the union said it will file for an injunction to annul the arrests and hold massive rallies in Seoul to protest against the court‘s decision. (Yonhap News)