The workers began striking at midnight Monday, said Alexei Etmanov, who heads the union at the factory in Vesvolozhsk, just outside St. Petersburg. They are seeking wage increases of about 30 percent and a 6 1/2-hour night shift, instead of 7 1/2 hours, he said.
Workers had held a warning strike Nov. 7, after three months of negotiations ended without agreement on their demands.
After a previous one-day strike in February, Ford agreed to raise wages by 14-20 percent and provide other improvements. Union officials at the time said the sides had agreed on the main sticking points, but that there would be further talks.
Yekaterina Kulinenko, a spokeswoman for ZAO Ford Motor Company, said most of the striking workers were barred from the factory, allowing only those working under an agreement to provide for operations to continue during the strike.
She also said management would not negotiate unless the strike is stopped.
Foreign automakers have rushed to open assembly plants in Russia to reach the growing number of consumers. Soaring world oil prices have boosted Russia's economy, lifting living standards and enabling more people to buy cars.
The Vesvolozhsk plant produced about 60,000 cars last year, mainly the Focus model, and plant officials hoped to increase production to 75,000 this year.
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