WASHINGTON — The legal fight against the Federal Communications Commission’s recent repeal of so-called net neutrality regulations began on Tuesday, with a flurry of lawsuits filed to block the agency’s action.

One suit, filed by 21 state attorneys general, said the agency’s actions broke federal law. The commission’s rollback of net neutrality rules were “arbitrary and capricious,” the attorneys general said, and a reversal of the agency’s longstanding policy to prevent internet service providers from blocking or charging websites for faster delivery of content to consumers.

Mozilla, the nonprofit organization behind the Firefox web browser, said the new F.C.C. rules would harm internet entrepreneurs who could be forced to pay fees for faster delivery of their content and services to consumers. A similar argument was made by another group that filed a suit, the Open Technology Institute, a part of a liberal think tank, the New America Foundation.

Suits were also filed on Tuesday by Free Press and Public Knowledge, two public interest groups. Four of the suits were filed in the United States Court of Appeals for the District of Columbia Circuit. The Free Press suit was filed in the United States Court of Appeals for the First Circuit.