Intracity bus drivers in 22 regions of the country, including Seoul, Busan, Incheon and Gyeonggi Province, are set to begin a general strike May 28. 

The Korean Automobile and Transport Workers’ Federation said the decision was reached Thursday during a meeting of union leaders for the 22 regions. 

The federation’s chair, Seo Jong-soo, said participants agreed to apply simultaneously on Monday for mediation of the labor dispute and to exert their best efforts in negotiations during the 15-day mediation period. 

Seo said the unions will go on strike simultaneously on May 28 in the event that no agreement is produced. 

The Seoul Bus Labor Union resumed its “work-to-rule” protest Wednesday, having begun the collective action a week earlier after wage negotiations broke down.