Around 20,000 of 377,000 articles uploaded on 10 health and lifestyle information websites run by DeNA Co. have plagiarism and copyright issues, the information technology firm announced Monday, disclosing the results of a three-month probe into the biggest "fake news" scandal to hit Japan so far.

A third-party investigative panel made up of four lawyers also concluded that up to 747,643 images used on the sites were copied from other websites in possible copyright violations.

In a more serious finding, 10 articles carried on the medical information site Welq possibly violated medical laws by propagating information that could cause damage to a person's health, the panel said.