SAN FRANCISCO - Yahoo Inc. has rebuffed Google Inc.'s attempt to learn more about its efforts to create digital copies of books, dealing the Internet search leader another setback as it prepares to fight against a copyright infringement suit.

In rejecting Google's request, Yahoo adopted the same stance taken last month by Internet retailer Amazon.com Inc.

Google believes it can defend its plans to provide online access to millions of library books by obtaining more details about similar projects involving some of its biggest rivals.

A group of publishers and the Authors Guild sued Google in a New York federal court last year, alleging the Mountain View-based company didn't get proper approval to make copies of books available to anyone with an Internet connection.

As its gathers evidence for its case, Google has subpoenaed Amazon.com, Yahoo and Microsoft Corp., among others.

Both Yahoo and Microsoft are part of a large alliance of businesses and libraries working together to create a digital database of books. Amazon.com has scanned a large number of books so consumers can read excerpts from books that they may want to buy.

Like Amazon.com, Yahoo lashed out at Google's request as a brazen attempt to pry into its trade secrets.

"There is simply no need for Google to be peering into the minds and computers of Yahoo employees," Yahoo's lawyer wrote in a 17-page list of objections delivered to Google last week.

Sunnyvale-based Yahoo provided The Associated Press with a copy of its objections Wednesday. The objections eventually may become public record if Google asks a judge to force Yahoo to comply with its subpoena.

As of late Wednesday, Google hadn't responded to a request for comment about Yahoo's objections.

Microsoft declined to discuss its response to Google's subpoena.