Other suspects may appear in a criminal case in which investigators have charged Russia's former economy minister Alexei Ulyukayev with extorting a $2 million bribe, unnamed sources told Russian news agencies on Wednesday.

President Vladimir Putin dismissed Ulyukayev on Tuesday over allegations he extorted the bribe from top oil producer Rosneft, a case that could expose fault lines in the Russian leader's inner circle.

Russian newspapers on Wednesday carried several stories saying ministers and aides close to Prime Minister Dmitry Medvedev might now be drawn into the same case as they were allegedly also under surveillance.