A fresh offer from a Microsoft delegation led by investor Carl Icahn was rejected by Yahoo over the weekend as negotiations became increasingly hostile.

Icahn wants to wrestle control of the board from chief executive Jerry Yang, put himself in control of the company and sell the search business to Microsoft.

Yahoo was given less than 24 hours to accept the proposal, the terms of which Microsoft said were not open to negotiation.

Yahoo chairman Roy Bostock said in a statement: "While this type of erratic and unpredictable behavior is consistent with what we have come to expect from Microsoft, we will not be bludgeoned into a transaction that is not in the best interests of our stockholders."

Yahoo said the advertising tie-in it had with Google was more lucrative than the Microsoft offer, and said a transaction to acquire the whole company would be much more straightforward and involve far less risk than splitting the firm.

Microsoft has rejected a repeated offer from Yahoo to sell the entire company to Microsoft at $33 (£17) a share.