Ontario's information and privacy commissioner has asked Google Inc. to fight a U.S. judge's ruling requiring the disclosure of details about users of the video-sharing site YouTube.

Ann Cavoukian said the ruling was "particulary disturbing from a privacy perspective" in a letter she sent Tuesday to Sergey Brin, Google's president of technology and one of the company's founders. The commissioner made her statement public on Thursday.

On July 3, U.S. District Court Judge Louis Stanton ordered Google to give media company Viacom the records of every video that users have watched on YouTube. The records include users' names and internet addresses.

Stanton made the ruling in a case where Viacom is suing Google for not doing enough to keep copyrighted TV videos, such as The Daily Show with Jon Stewart, off YouTube, which Google owns.

Cavoukian's letter said she sympathized with the right of intellectual property holders, but "it is not acceptable to allow copyright enforcement to come at the expense of users' privacy."

She said that a related order by Stanton limiting the use of the data isn't good enough protection of privacy, because "companies simply cannot guarantee that information, once obtained, will not be subject to unauthorized use or disclosure."

She suggested a legal strategy Google might follow, writing that Stanton's order ignored parts of the U.S. Video Privacy Protection Act.