Exclusive: Google’s privacy push draws U.S. antitrust scrutiny - sources

FILE PHOTO: A Google search page is seen through a magnifying glass in this photo illustration taken in Berlin, August 11, 2015. REUTERS/Pawel Kopczynski/File Photo

(Reuters) - Google's plan to block a popular web tracking tool called "cookies" is a source of concern for U.S. Justice Department investigators who have been asking advertising industry executives whether the move by the search giant will hobble its smaller rivals, people familiar with the situation said.

Alphabet Inc's Google a year ago announced it would ban some cookies in its Chrome browser to increase user privacy. Over the last two months, Google released more details, leading online ads rivals to complain about losing the data-gathering tool.