Sept 13 (Reuters) - The Federal Election Commission (FEC) has dismissed a claim that Twitter Inc violated election laws when it prohibited users from posting links to a New York Post story about then-presidential candidate Joe Biden's son, according to a source familiar with the matter.

The Republican National Committee lodged a complaint after the social media site blocked the story link in October. The RNC argued that Twitter blocking the story meant it was illegally contributing to Democratic candidate Biden's presidential campaign.

The election regulator determined that Twitter's actions were allowable because it was enacted with a valid commercial reason and not for a political purpose, according to The New York Times, which first reported the FEC's dismissal on Monday.

The FEC, Twitter and News Corp, which owns the Post, declined to comment. The RNC did not immediately respond to a request for comment.

The New York Post's editorial board defended its story in an op-ed published on Monday, saying that the people involved in the emails it published had confirmed the contents.

The New York Post story contained https://www.reuters.com/article/us-usa-election-social-media/twitter-facebook-restrict-users-dissemination-of-new-york-post-story-on-biden-idUSKBN2700EZ alleged details of Hunter Biden's business dealings with a Ukrainian energy company and said that Joe Biden had met with an adviser of the company. Some disinformation researchers raised red flags about the provenance and credibility of the story.

Twitter said at the time that the story violated its "hacked materials" policy, which bars the distribution of content obtained through hacking that contains private information or trade secrets. It provided no details on what materials it viewed as hacked in the Post articles.

Soon after the incident, Twitter changed its hacked materials policy and later said it had stopped https://www.reuters.com/article/us-usa-election-twitter-idUKKBN27121P blocking the story when the private information in it had become widely available in the press and on other platforms. CEO Jack Dorsey also said in a tweet that "straight blocking of URLs was wrong." (Reporting by Elizabeth Culliford in London and Sheila Dang in Dallas; Editing by Rosalba O'Brien)