A federal antitrust probe targeting Facebook appears to have entered its late stages, according to three people familiar with the matter, as Republican and Democratic leaders on the Federal Trade Commission huddled privately Thursday to discuss their next steps in the case.

The development typically signals the FTC is nearing the end of its work, said the people, who spoke on the condition of anonymity to discuss a law enforcement matter and cautioned that the agency’s exact timing remains unclear. A federal lawsuit against the social networking giant would spark another lengthy legal war between Washington and Silicon Valley after the Justice Department accused Google of violating antitrust laws in a case filed earlier this week.

Facebook and the FTC each declined to comment.

FTC officials initiated their antitrust investigation into Facebook last June, on the heels of the agency’s privacy probe targeting the company. That investigation — spurred by a series of scandals, including Facebook’s entanglement with Cambridge Analytica, a political consultancy — resulted in the social media company paying a $5 billion fine and instituting other changes to its business practices.

The FTC’s subsequent antitrust probe has focused on Facebook’s dominance in social networking and its past purchases of Instagram, a photo-sharing app, and WhatsApp, a messaging service, the people familiar said. Some regulators and antitrust experts believe the transactions, which federal officials in the past essentially blessed, ultimately have solidified Facebook as a monopoly that no social media start-up can challenge — thanks in large part to the immense amounts of data Facebook has obtained from its billions of users globally.

Facebook, however, has fiercely defended its business practices. When House lawmakers sharply criticized the company as part of their own recent antitrust probe into Big Tech, Facebook stressed that it faces competition from a wide variety of services — and that it should not be penalized because Instagram and WhatsApp have grown exponentially due to its company’s investments.

“A strongly competitive landscape existed at the time of both acquisitions and exists today,” spokesman Chris Sgro said in a statement earlier this month. “Regulators thoroughly reviewed each deal and rightly did not see any reason to stop them at the time.”

The FTC meeting comes days after the U.S. government filed its long-awaited antitrust lawsuit against Google. The Justice Department’s complaint — backed by 11 states, and potentially more to come — contends the search giant struck special deals and relied on other problematic business practices to ensure the primacy of its search engine across desktop computers, smartphones and a range of apps and other services.