President Vladimir Putin has indicated that some of the country's best-known tycoons may be investigated to see if they amassed their wealth illegally.
Putin's words could cause a quake in Russia's private business sector
Many of the country's wealthiest business people made their money following post-Soviet privatisations.
Some are thought to have broken the law in a rush to gain from the free market.
The news came as Russia's richest man lost a fight for bail as he awaits trial on charges of embezzlement and tax evasion totalling more than $1bn.
'Complicated and confusing'
Mr Putin told the Russian chamber of commerce on Tuesday that while he was not considering re-nationalising former state-run industry, he was keen to enforce the law.
"The laws were complicated and confusing [in the period immediately following the collapse of the Soviet Union], this is true, but they could have been followed in full.
"Those who wanted to respect the laws did so," he said.
He added: "You must take this into account: those who consciously stole should not get preferential treatment compared to those who behaved
well and respected the law.
"Perhaps they [people who followed the law] may not have earned as much, but they feel at ease and sleep well."
The BBC's Steve Rosenberg in Moscow says Mr Putin's words are likely to spread fear amongst Russia's oligarchs, the country's business elite, who struck rich under former President Boris Yeltsin by using connections and guile to buy state assets at knock-down prices.
Former Yukos oil boss Mikhail Khodorkovsky, who was remanded in custody for another three months on Tuesday, is latest oligarch to face criminal charges.
Others, including Boris Berezovsky and Vladimir Gusinsky, now live abroad.