The Federal Trade Commission sent the request for information as part of its investigation into allegations that Google uses its monopoly in search to favor the company's other services.

Bloomberg said that other handset makers and wireless carriers also were sent the subpoenas.

The information requests follow talks in 2010 between Apple and Microsoft over whether Bing would replace Google as the default search on the iPhone. Apple went with Google, and the two companies share the resulting ad revenue.

A FTC spokeswoman declined comment. Google also declined comment and Apple did not respond to a request for comment.

Google has been broadly accused of using its clout in the search market to shut out rivals, like travel search, by putting them low in search results.

In January, regulators expanded the probe to include Google+, the search giant's new social networking tool, which launched last June and offers many of the capabilities available on Twitter and on Facebook.

(Reporting By Diane Bartz; editing by Carol Bishopric)

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