George Bush has failed to outline any new proposals to help soothe worries on world markets, which have suffered for another day.

In an address to the American public the United States president pledged to act aggressively to stop the tide of mass sell-offs.

The Dow Jones slumped down eight per cent moments after opening earlier, mirroring slumps on the FTSE 100 in London and European and Asian markets.

The panic-selling came despite two rescue packages worth $700 billion and £500 billion on both sides of the Atlantic, while central banks announced a coordinated 0.5 percentage point interest rate cut on Wednesday.

Speaking at the White House ahead of a meeting of G7 finance ministers, Mr Bush said: “The US government is acting and will continue to act to add stability to markets.

“Banks have suffered losses,” he said, “creating uncertainty and anxiety among our people. Anxiety can feed anxiety… making it hard to see the problem.”

He outlined his government’s recent moves to confront the crisis – including the controversial $700 billion bank bailout plan, initiatives to reduce the number of repossessions, saver guarantees, support for the commercial paper market, and the released of hundreds of billions of dollars into the markets from the Federal Reserve to provide grease to the liquidity crisis.

“We are sending out an unmistakeable signal we are in this together and will come through this together,” Mr Bush explained.

“The plan we are executing is aggressive and right… It will take time and is flexible… and big enough to work.

“This is an anxious time, but American people can be confident… We know what the problems are, we have tools to fix them and are working to do so.”

On an already volatile day, the Dow Jones dropped following the White House statement.

At 10:52 EDT (15:52 BST), the index was down 2.79 per cent to 8,340.08 – after dropping on opening, regaining its position and falling once more.