Police put the total number of people at the rally at 17,000, RIA Novosti reported. They waved signs saying "Russia needs a strong president."
Putin is seeking a return to the presidency. Opposition leaders accuse his United Russia Party of fraud in recent parliamentary elections and have been holding demonstrations in Moscow and other large cities.
The organizers of Saturday's rally work for Uralvagonzavod, a state-owned enterprise that began manufacturing tanks during World War II. Igor Kholmanskikh, a worker at the factory, told Putin during a call-in show in mid-December employees there wanted to show their support in the face of opposition demonstrations.
"If our police are unable to work or cope then I and my mates are ready to come ourselves and ensure stability -- of course within the limits of the law," he said.