Once again, Yahoo! (YHOO) has rebuffed an offer from software giant Microsoft (MSFT) - Get Report.

Yahoo! announced Saturday night that Microsoft, along with billionaire investor Carl Icahn, had proposed on Friday a restructuring of Yahoo! that would entail Microsoft acquiring Yahoo!'s search business.

In a

press release

, Yahoo! said Microsoft and Icahn gave it 24 hours to make a decision on the proposal. Yahoo! added that Microsoft and Icahn made it clear they were "unwilling" to negotiate on the proposal's fundamental terms.

"This odd and opportunistic alliance of Microsoft and Carl Icahn has anything but the interests of Yahoo!'s stockholders in mind," said Roy Bostock, Yahoo!'s chairman, in a news release. "Clearly, Microsoft, having failed to advance in search, is aligning with the short-term objectives of Mr. Icahn to coerce Yahoo! into selling its core strategic search assets on terms that are highly advantageous to Microsoft, but disadvantageous to Yahoo! stockholders."

Yahoo! said its recently signed agreement with Internet search leader


(GOOG) - Get Report

is superior to the Microsoft/Icahn proposal, which Yahoo! added would also preclude the sale of all of Yahoo! for a "full and fair price."

Yahoo!'s board is engaged in an increasingly nasty battle with Microsoft and Icahn over the fate of the search company. Last week,

Icahn revealed

he had spoken with Microsoft CEO Steve Ballmer about having Microsoft negotiate with members of a new Yahoo! board that Icahn hopes to have elected at Yahoo!'s annual meeting next month.

Yahoo! shares gained 7 cents Friday to close at $23.57. Microsoft stock ended the session down 20 cents at $25.25.

This article was written by a staff member of TheStreet.com.