Local courts have rejected arrest warrants for eight rail union leaders, court officials said Wednesday, in a blow to a police probe into the nation's longest rail strike.

On Saturday, police requested warrants to formally detain eight executives of provincial offices of the state rail company's union. All are alleged to have played major roles in the recently-ended strike and are awaiting trial.

But courts, including the Seoul Western District Court and the Daejeon District Court, turned down all the requests on Tuesday, court officials said. They reportedly cited the unlikelihood of the suspects attempting to flee as the reason for the rejection.

Police and prosecutors have vowed no leniency toward those who led the "illegal strike," which the rail company claims caused huge economic losses even after the strike came to an end on Dec. 30.

The authorities have since arrested 22 union leaders with court-issued arrest warrants. Police again requested warrants to formally detain twelve of them facing relatively serious charges for further questioning. Courts, however, have allowed detention of only two of them.

Thirteen executives of the union's headquarters, including union head Kim Myung-hwan, are still wanted by the police.

Police say they are not currently considering again filing for arrest warrants for the eight leaders following Tuesday's court decisions.

The union of the state-run Korea Railroad Corp. (KORAIL) went on strike for more than three weeks last month in protest of 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. (Yonhap News)