Some 1,500 workers have gone on strike at the main assembly line of Russia's largest automaker, AvtoVAZ, causing the company up to $40 million in losses this week alone, a senior official said Friday.


The workers have been on strike for four days demanding paychecks for August, an aide to the factory's general director said in a telephone interview from Togliatti, AvtoVAZ's hometown on the Volga River.


The official, who declined to be named, said that as of Friday the plant was more than 7,500 cars behind their production schedule because of the strike. The average factory price of AvtoVAZ cars is about $5,000.


Negotiations between union leaders and factory managers continued Friday, but it was not clear if the parties were nearing an agreement, the official at the factory said. Union officials could not be reached for comment Friday.


The market value of AvtoVAZ shares was not at all affected by the news of the strike, with stock selling for about 16,500 rubles ($6.20) Friday, according to Pavel Yasenkov, an expert with Skate-Press Consulting Agency. Yasenkov said the share price was stable through the week.


The strike at AvtoVAZ began Tuesday afternoon when workers at the main assembly line demanded their paychecks for August.


The official said that workers were unhappy with the company's pay system, which delays paychecks for a month. He said the system was based on an agreement between workers and the administration struck earlier this year.


Under the agreement, August salaries are due to be paid between Oct. 1 and Oct. 10, the official said, adding that the average monthly wage at AvtoVAZ is 500,000 rubles. The official said that cash shortages at AvtoVAZ have become a chronic problem.


"Our customers do not pay, but we cannot stop deliveries because we cannot store more than 9,000 cars at the factory," the official said, adding that AvtoVAZ's daily output this year has averaged 2,500 cars. "If we halted deliveries, we would hurt ourselves."


AvtoVAZ produced 673,000 cars in 1993 and plans to manufacture 675,000 this year. The company halted production for all of January to replace some of its equipment.