Tens of thousands of Hyundai Motor's unionized workers staged a full-day strike for the first time in a decade, bringing production to a complete halt as they pressed demands for better wages and job protections. The daylong strike at the South Korean automaker, the first since 2016, followed months of failed wage negotiations and a series of partial walkouts.

All Hyundai Motor and sibling Kia factories in South Korea went quiet from Friday morning, as tens of thousands of workers downed their tools after the union ratcheted up the walkout to eight hours per shift—there are two eight-hour shifts each weekday—from the previously planned four hours, according to the company and union leaders.

Some striking union members attended a rally in Seoul, while assembly lines at the plants remained idle ahead of the weekend, with partial four-hour walkouts set to resume next week.