Watch John Devitt's report on the "power-sharing formula"

The agreement will allow a new government to be formed with a mandate to tackle the economic crisis.

The BBC's Angus Roxburgh: "A substantial shift of power"

Under the agreement, no-one will attempt either to dismiss the government or dissolve parliament for 18 months.

Constitutional changes which would strip President Yeltsin of some of his key powers are to be drawn up within a month.

Deal follows talks between Mr Chernomyrdin and Duma

Changes to Russian media legislation are also reported to be included, on the insistence of the Communist party, which dominates the Duma.

Duma First Deputy Chairman, Vladimir Ryzhkov, said the changes would strengthen public control and create public monitoring councils in the state broadcast media.

The agreement has been forwarded to Mr Yeltsin for approval.

President Yeltsin may be reduced to a figurehead

Mr Yeltsin's representative in the Duma, Alexander Kotenkov, was cautious. "I am personally happy with the document, but I don't know how the president will take it," RIA news agency quoted him as saying.

The BBC Correspondent in Moscow, Paul Anderson, says Mr Yeltsin may now find his role reduced to that of a figurehead.

Russian political analyst Dmitri Trenin: "The political crisis is not over"

He would, however, still control the appointment of the foreign, defence, interior and security ministries - the so-called "power ministries".

Our correspondent says the agreement is a victory for the country's Communist party.

Communist leader Gennady Zyuganov: may press IMF

The Communist leader, Gennady Zyuganov, has indicated that he may press for changes to Russia's loan agreement with the International Monetary Fund on Monday, when the Duma is scheduled to vote on Mr Chernomyrdin's appointment as prime minister.

BBC Russian Affairs Analyst Stephen Dalziel: "Important gain for deputies"

Alexander Shokhin, leader of Mr Chernomyrdin's party, Our Home is Russia, said: "If the president approves the document and signs it, this will lead to the speedy approval of Chernomyrdin's candidacy, there should be no delays."

Washington pledges support

A miner protests in Red Square

World markets have been rocked by the deepening economic and political crisis over the past week.

Share values swung violently up and down as investors reacted to events and rumours.

In Washington, a White House spokesman described as encouraging Mr Chernomyrdin's assurances that Russia would continue with economic reforms.

The United States President Bill Clinton is due to fly to Russia on Tuesday for a three-day summit with Mr Yeltsin, which is was due to include discussions on the economic crisis.

However, the speaker of the US House of Representatives, Newt Gingrich, said the summit would be a meeting of two weakened leaders simply propping each other up.