The Federal Trade Commission and 17 state attorneys general filed an antitrust lawsuit against Amazon today, alleging the e-commerce behemoth uses its position in the marketplace to inflate prices on other platforms, overcharge sellers and stifle competition.

The lawsuit, filed in U.S. District Court for the Western District of Washington, is the result of a years-long investigation into Amazon’s businesses and one of the most significant legal challenges brought against the company in its nearly 30-year history.

According to a news release sent by the agency, the FTC and states that joined the lawsuit are asking the court to issue a permanent injunction court that they say would prohibit Amazon from engaging in its unlawful conduct and loosen its “monopolistic control to restore competition.”

“The complaint sets forth detailed allegations noting how Amazon is now exploiting its monopoly power to enrich itself while raising prices and degrading service for the tens of millions of American families who shop on its platform and the hundreds of thousands of businesses that rely on Amazon to reach them,” FTC chairman Lina Khan said in a statement.

Many had wondered whether the agency would seek to a forced break-up of the retail giant, which is also dominant in cloud computing and has a growing presence in other sectors like groceries and health care. In a briefing with reporters, Khan dodged questions of whether that will happen.

“At this stage, the focus is more on liability,” she said.