Workers at Ford’s Russian assembly plant are staging a go-slow strike in a dispute over wages, union and company officials reportedly said on Tuesday.

According to Reuters , the factory in St Petersburg, Russia’s second city, was one of the first to be opened in the country by a foreign car maker and plans to turn out 36,000 Focus models this year. It is Ford’s only plant in Russia.

“The go-slow strike has started. We are working strictly to rule, we are not exceeding our targets and therefore production levels at the factory have fallen,” a member of the plant’s strike committee told Reuters .

A spokeswoman for Ford’s Russian operations, Yekaterina Kulinenko, told the news agency cars were still coming off the assembly line. She said she could not put a figure on how much the strike action would cost the company.

“Ford is ready to hold negotiations, and meetings with the unions continue. But strike action is not a constructive way of dealing with this dispute,” Kulinenko reportedly said.