Workers broke down negotiations with management of Ford's only Russian manufacturing plant, sending a strike at the factory into its sixth day.
About 1,500 workers halted production at the Vsevolozhsk plant, near St. Petersburg, on Nov. 20 in a dispute over wages and overnight work hours.
Negotiators for both the union and ZAO Ford Motor Company management met for 1½ hours Monday, and management agreed in principle to raising wages, but did not give concrete figures, union chief Alexei Etmanov said.
"We haven't agreed on anything," he said.
Workers want their wages increased by about 30 percent, and their night shifts reduced to 6½ hours, from 7½ hours.
Ford spokeswoman Yekaterina Kulinenko did not respond to phone calls seeking comment.
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 points, but that there would be further talks.
Workers then held a warning strike Nov. 7, after three months of negotiations ended without agreement.
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 Vsevolozhsk plant produced about 60,000 cars last year, mainly the Focus model, and plant officials have said they were hoping to increase production to 75,000 this year.