Factory employees called the strike to demand higher wages. A worker participating in the strike at the AvtoVAZ factory, in the city of Tolyatti, told RFE/RL that workers earn an average monthly salary of $420, while middle managers are paid up to $5,400 per month.
He said a trade-union official backing the strike was detained by police on July 31.
Avtovaz has accused "certain political forces" of being behind the strike, which has been met with a heavy security presence at the factory.
(with material from agency reports)