TOKYO — Japan’s antitrust watchdog said today that U.S. search giant Google must fix its advertising search restrictions affecting Yahoo in Japan.

The Japan Fair Trade Commission said in a statement that its recent study of Google’s practices showed it was undermining fair competition in the advertising market.

Google said in an emailed statement that it has cooperated fully with the commission’s probe, and stressed the commission has not found it had outright violated anti-monopoly laws. It promised to carry out the commission’s directives to offer “valuable” search functions to Japanese users and advertisers.

Yahoo has merged with Japanese social media platform Line, and Line Yahoo declined comment.

The alleged questionable practices by Google began about a decade ago and continued for more than seven years, according to the commission.

Google will be under review for the next three years, to ensure it carries out needed changes, the commission said. There is no immediate fine or other penalties for Google, which remains popular among Japanese.

The commission’s move follows another setback for Google in Japan. Last week, Japanese doctors filed a civil lawsuit against the company, demanding damages for what they claim are groundless derogatory and often false comments.

The Tokyo District Court suit demands 1.4 million yen ($9,400) in damages for 63 medical professionals, for reviews posted on Google Maps.

Google said in response that it’s working “24 hours a day” to reduce misleading or false information on its platform, combining human and technological resources “to delete fraudulent reviews.”