Chinese labour protests that have forced shutdowns at foreign factories have spread beyond south China’s industrial heartland, posing a dangerous new challenge for Beijing.

Workers at a Taiwanese machinery factory outside Shanghai clashed with police on Tuesday, leaving about 50 protesters injured. The confrontation represented an escalation of recent industrial action in the country, which until this week had been largely peaceful and concentrated in southern Guangdong province.

The violence at KOK International in Kunshan, a factory town in southern Jiangsu province, came just a day after Honda struggled to contain the fallout from its second strike in as many weeks. That strike, at Foshan Fengfu Autoparts, a joint venture majority held by a Honda subsidiary, forced the Japanese carmaker to suspend production at its car assembly plants in nearby Guangzhou, the capital of Guangdong province.