The Federal Trade Commission filed the new complaint in federal court in Washington, alleging that Facebook violated antitrust laws by buying Instagram and WhatsApp to eliminate them as competitors.

The agency is trying to revive the case after US District Judge James Boasberg in June dismissed it, saying the agency failed to provide enough detail to support its claim that Facebook has a monopoly in the social media market. Boasberg had given the FTC 30 days to fix the error and refile, and the commission won an extension until 19 August.

First filed in December, the Facebook case presents an early test for FTC Chair Lina Khan, who was named head of the agency in June by President Joe Biden.

Khan is a leading advocate for taking a more forceful antitrust stance against companies and is already taking steps to bolster the agency's authority. Facebook is seeking to bar Khan from participating in the case, arguing that her academic writing about the company and her work on the House antitrust panel, which investigated Facebook and other tech platforms, showed she is biased.