The action by the attorneys general, which has been anticipated for weeks, could possibly be expanded to other companies beyond Google and Facebook, some of the people said.

Public opinion polls suggest Americans are increasingly growing disenchanted with tech companies, in particular social media platforms, even as they remain hooked on their services.

One of the main concerns among regulators, lawmakers and state attorneys general is the dominant role a handful of big tech companies have in commerce and communications.

“The extreme concentration in the technology industry is bad for the consumer, and in our opinion it’s bad for America,” Tennessee Attorney General Herbert Slatery III said at a June hearing on antitrust concerns in the tech industry, flanked by two other state attorneys general. “The concentration has stifled innovation with market distortions [in] research and development, as entrepreneurs avoid competing with Google and Facebook and other tech giants. So we need to do something about that.”