Regulators at the Federal Communications Commission have restarted their formal review of Comcast Corp.'s proposed $45 billion acquisition of Time Warner Cable Inc.

A newly organized group, the Stop Mega Comcast Coalition, used the FCC's action Wednesday to ask the government to reject the proposal.

The coalition consists mostly of companies and nonprofits that previously have criticized the deal, which would merge the nation's largest and second-largest cable-TV companies.

"Mega Comcast would control an unprecedented 50 percent of the high-speed broadband wires across the country, and would be on a path to virtual dominance of the high-speed broadband market given that the combined company will pass two-thirds of U.S. households," Gene Kimmelman, president and chief executive officer of the nonprofit group Public Knowledge, said in a statement Wednesday.

Kimmelman testified against the deal in a Senate hearing this year.

Comcast cheered the FCC's action and said it still believes the agency could finish the review in early 2015, noting that hundreds of organizations nationally support the deal.

"Americans are supportive of the Comcast-TWC transaction because they understand the significant benefits it will bring to consumers and the broader public," Comcast spokeswoman Sena Fitzmaurice said. "By spending hundreds of millions of dollars annually to upgrade the Time Warner Cable and Charter [Communications Inc.] networks, millions of Americans will enjoy faster Internet speeds, better technology, greater access and Net Neutrality protections."

The FCC suspended the Comcast/Time Warner Cable review on Oct. 3 to obtain more information from Comcast and Time Warner Cable.

Then it extended the pause while a federal appeals court ruled on opposition by CBS Corp. and other content companies that argued they should not have to disclose sensitive business information as part of the FCC review.

As part of the same action Wednesday, the FCC resumed its review of AT&T Inc.'s proposed deal to acquire DirecTV, which would combine one of the nation's largest wireless companies with the nation's largest satellite-TV operator.

That review had been halted for the same reasons.

The agency seeks to conclude the merger reviews in 180 days, and is restarting the Comcast/Time Warner Cable proposal at Day 85, or slightly more than halfway through the process.