Iron Man, Captain America and Spider-Man greet visitors to Disney's website, but parents may be surprised to learn that these superheroes may also open the door to tools that track their children's activities across the Web, according to federal complaints to be filed Wednesday.

The filings with the Federal Trade Commission accuse Disney's Marvel subsidiary, as well as the Japanese firm Sanrio, of flouting new privacy rules for children by collecting personal information from users without verifying that they are older than 13.

Marvel declined comment on the complaint. Sanrio, known for its Hello Kitty character, did not immediately respond to a request for comment.