The U.S. government may try to stop Facebook from integrating its various platforms — Instagram, Messenger and WhatsApp — in a move that has become a core objective for the company as it faces increasing regulatory scrutiny, according to three sources with knowledge of the matter who were not authorized to speak publicly.

Facebook has been the subject of an antitrust investigation by the Federal Trade Commission, the federal government’s main business regulator, which has been looking at the company’s dominance in social networking and online advertising. Facebook’s acquisitions have also been part of that investigation.

The FTC could seek a preliminary injunction to stop Facebook from weaving its disparate parts together. An injunction could deal a severe blow to Facebook and its efforts to combine its services, which began earlier this year. It would also leave the company more vulnerable to being broken up.

The news of the FTC's considerations was first reported by The Wall Street Journal.

The injunction is one of several steps the FTC is considering as it looks to check Facebook's power and address concerns that the company's growing size may reduce competition among social networks.

Pursuing an injunction would be an extraordinary step for the FTC, which does not typically try to undo mergers that have already happened. Facebook bought Instagram in 2012 and WhatsApp in 2014. The five-member commission would need to vote to pursue the injunction and then file suit in federal court. The FTC would also need to prove that Facebook was in violation of antitrust law.

With regulatory concerns looming, Facebook Chief Executive Mark Zuckerberg announced in January that he would work to integrate Facebook's family of apps to create more seamless messaging between the various services.

Facebook's critics also saw the step as a pre-emptive move to make it harder for Washington to break up the company.

Facebook shares dropped sharply on Thursday, declining about 2.7 percent.

Facebook has become the subject of broader scrutiny of politicians, many of whom have weighed in with plans to either break up or further regulate Facebook.

Sen. Richard Blumenthal, D-Conn., tweeted that injunctions "must only be the start."

"Facebook’s rapacious consolidation & integration of Instagram, WhatsApp & Oculus is an affront to our antitrust laws," Blumenthal wrote. "The FTC & DOJ cannot continue to leave Facebook’s provocations & anti-competitive conduct unchallenged. Action is overdue."