WASHINGTON — Many supporters of the blockbuster Comcast-Time Warner Cable merger breathed a sigh of relief on Sunday, when AT&T and DirecTV announced plans to merge, thinking the latest pairing would divert some regulatory scrutiny of the other high-stakes deal.

Perhaps some gasps of concern were also in order.

On Monday, opponents of the consolidation in the telecommunications industry — including on Capitol Hill — latched onto the AT&T and DirecTV deal, arguing that such rapid merging in the markets for cable television, high-speed Internet and telephone service should lead regulators to hit the brakes on all such deals.

But while both sides declared that the latest deal helped their cause, antitrust experts said the truth was more murky. While the deals are similar in some ways, they say, including blurring the lines between sectors of the telecommunications business, the two mergers are also different in significant ways that could lead regulators to separate conclusions for each one.

Just one thing is certain: The deals will force antitrust officials to undertake months of digging and analysis to determine whether the multibillion-dollar mergers will squelch competition, leading to higher prices for consumers.