Unionists at Citibank Korea Inc., a local unit of U.S.-based Citigroup Inc., said Friday they are ready to go on strike to protest branch closures and restructuring plans by the bank management. The 3,200-member union voted earlier this week in favor of a walkout in an overwhelming majority of 91.6 percent. Their strike would be the first at a local bank in three years since the strike at the Standard Chartered Bank Korea in 2011 when unionists protested the introduction of a performance-based management system.