The Federal Trade Commission sued Amazon on Monday, alleging that the company manipulated prices for advertisements on its e-retail platform. Court records show that more than 20 U.S. states joined the action as co-plaintiffs.

The filing follows a report from The Wall Street Journal that the agency planned to bring the case. The lawsuit targets Amazon's practices in setting and adjusting ad prices for sellers using its marketplace.

Amazon operates the largest e-commerce platform in the United States. The company has faced multiple regulatory actions in recent years from federal and state authorities over competition and consumer issues.

The states participating in the suit add significant weight to the federal complaint. Their involvement typically signals coordinated enforcement efforts across jurisdictions.

Details from the complaint remain limited at this stage. The FTC and the states seek remedies that would address the alleged pricing practices for ads.

Amazon has not yet issued a public response to the filing. The company has previously defended its advertising tools as beneficial to sellers and consumers alike.

This case adds to ongoing scrutiny of major technology platforms by government regulators. The outcome could influence how online marketplaces structure their advertising systems going forward.