If approved by the public, the proposals would transfer power from the presidency to parliament.

Mr Putin is due to step down in 2024 when his fourth term of office comes to an end.

But there is speculation he could seek a new role or hold on to power behind the scenes.

Mr Putin put forward his plans in his annual state of the nation address to lawmakers. Later, in an unexpected move, Prime Minister Dmitry Medvedev announced that the government was resigning to help facilitate the changes.

Russian government sources told the BBC that ministers did not know about the government's resignation ahead of the announcement.

"It was a complete surprise," one source said.

The Russian leader said during a speech to both chambers of parliament that there would be a nationwide vote on changes that would shift power from the presidency to parliament.

Constitutional reforms included giving the lower house of parliament, the State Duma, "greater responsibility" for the appointment of the prime minister and the cabinet.

Currently, the president appoints the prime minister, and the Duma approves the decision.

Mr Putin also suggested an increased role for an advisory body called the State Council. The council, which is currently chaired by Mr Putin, comprises the heads of Russia's federal regions. Mr Putin said it had proved to be "highly effective".

Mr Medvedev made his announcement on state television with President Putin sitting next to him.

"These changes, when they are adopted... will introduce substantial changes not only to an entire range of articles of the constitution, but also to the entire balance of power, the power of the executive, the power of the legislature, the power of judiciary," Mr Medvedev said of Mr Putin's proposals.

"In this context... the government in its current form has resigned."

Mr Putin thanked Mr Medvedev for his work but said "not everything" had been accomplished.

He asked Mr Medvedev to become deputy head of the National Security Council, which is chaired by Mr Putin.

The president later nominated tax service chief Mikhail Mishustin to replace Mr Medvedev as prime minister.