Google said on Monday it was concerned about the free flow of information on the Internet if Microsoft were to succeed in acquiring Yahoo. Last month, Microsoft proposed buying Yahoo in a deal originally worth $44.6 billion, but Yahoo's board has rejected the offer, saying it was too low.

"We would be concerned by any kind of acquisition of Yahoo by Microsoft," Chief Executive Eric Schmidt told reporters.

"We would hope that anything they did would be consistent with the openness of the Internet, but I doubt it would be."

Schmidt pointed to Microsoft's past history and "the things that it has done that have been so difficult for everyone", but he did not elaborate.

"We are concerned that there are things Microsoft could do that would be bad for the Internet," said Schmidt.