The Tass news agency reports that Russian Prime Minister Dmitry Medvedev submitted his resignation to President Vladimir Putin on Wednesday.
Russian news agencies said Putin thanked Medvedev for his service but noted that the prime minister's Cabinet failed to fulfill all the objectives set for it.
Russian media said Putin plans to name Medvedev as deputy of the presidential Security Council.
Medvedev, a longtime close associate of Putin's, has served as Russia's prime minister since 2012. He spent four years before that as president in 2008-2012.
Putin asked the members of Medvedev's Cabinet to keep working until a new Cabinet is formed.
Medvedev's resignation followed Putin's annual state of the nation address earlier Wednesday. During his speech, the Russian leader proposed amending the constitution to increase the powers of prime ministers and Cabinet members.
The proposed move is seen as part of Putin's efforts to carve out a new position of power for himself to stay at the helm after his current term as president ends in 2024.