This is a surprise move that may expose fault lines in Vladimir Putin’s inner circle.
Ulyukayev, 60-year-old technocrat whose ministry has been overseeing sell-off of state asset, is the highest-ranking official to be detained while in office since the collapse of the Soviet Union in 1991.
State television was quick to present his detention as part of the authorities’ fight against corruption.
It may also be evidence of infighting at the highest levels of power and may herald a wider shake-up before the 2018 presidential election.
The Investigative Committee said Ulyukayev had extorted a $2 million bribe from Rosneft in exchange for signing off its purchase of a stake in mid-sized oil producer, Bashneft.
It is the state agency that investigates major crimes.
“The minister is detained,” the committee said in a statement in the early hours, adding that it had opened a criminal case against him.
Medvedev and Putin spoke about the detention, Medvedev’s office said, adding: “The prime minister believes that the most painstaking investigation of this case is required.”
The minister has been in his job since June 2013.
He is not part of Putin’s inner circle, dominated by people favouring commanding key economic role for the state; he is neither part of rival camp of economic liberals.
Ulyukayev is close to Andrei Kostin, the influential head of Russia’s second-biggest lender, state-owned VTB, and chairs VTB’s supervisory board.