The arrest of Russia's economic development minister is an "extraordinary event for the government and authorities in general," Prime Minister Dmitry Medvedev has said.
Aleksei Ulyukayev was sacked on November 15 after he was charged with extorting a $2 million bribe from Russia's state-owned oil giant, Rosneft.
A court ordered that Ulyukayev, who denies the charges, remain under house arrest until mid-January.
Speaking at a government meeting on November 16, Medvedev called for a thorough investigation into the case, which he said highlights that "absolutely all citizens" are equal before the law.
"The court should close the chapter on the whole process," he said.
Ulyukayev, who had served as economic development minister since 2013, is the highest-ranking Russian official held since the 1991.