U.S. antitrust regulators told Google they opened a formal investigation into whether the dominant search company illegally abuses its market power.

Google said on its Official Google Blog that it received formal notification from the U.S. Federal Trade Commission that it has begun a review of our business. The notification came on Thursday, they said.

The company, which dominates U.S. and global markets for search advertising, has been accused by competitors of favoring its own services over rivals in its search results.

Google defended its practices, saying it focused on the consumer. It's still unclear exactly what the FTC's concerns are, but we're clear about where we stand. Since the beginning, we have been guided by the idea that, if we focus on the user, all else will follow, Google said in the blog.

(Reporting by Diane Bartz; Editing by Derek Caney)