Capitol Hill lawmakers responded with concern Monday to AT&T's proposed purchase of DirecTV.
"I will closely monitor the [Federal Communications Commission] and the antitrust authorities' response to this announcement," Leahy said. "The Senate Judiciary Committee will be looking closely at this transaction."
Sen. Al Franken, D-Minn., told CNN's "New Day" program the proposed $49 billion deal "is a bad trend" that threatens to hit average Americans in their pocketbooks.
"I'm very skeptical," said Franken, a member of the Senate Judiciary panel. "This usually leads to higher fees for consumers and less choices."
"We need to keep as much competition in this space. This is going in exactly the wrong direction."
Franken added the proposal deal warrants congressional hearings.
Telecommunications giant AT&T and satellite TV provider DirecTV on Sunday announced plans to unite, promising consumer benefits such as more economical bundles that tie mobile phone, pay TV and Internet service together on a single bill.
A bipartisan group in the House Judiciary Committee, including Chairman Bob Goodlatte, R-Va., and ranking member John Conyers, D-Mich., issued a joint statement promising the panel will closely review the deal, including holding a hearing, "to ensure that consumers' interests are protected in an increasingly consolidated telecommunications marketplace."
The deal would create the second-largest pay TV operator behind a proposed merger $45 billion merger of Comcast-Time Warner Cable, which would serve 30 million subscribers.
The AT&T-DirecTV proposal could face regulatory scrutiny from the Federal Communications Commission and the Justice Department because it would effectively cut the number of Internet-delivered video providers from four to three for about 25 percent of U.S. households.
The federal regulators also are looking closely at the potential Comcast-Time Warner Cable partnership, announced in February, as it would consolidate unprecedented control of what viewers watch and download. Watchdog groups also are concerned, saying the new company would wield too much power and that it ultimately would raise the price of high-speed connections.
It also represents another giant expansion following Comcast's $30 billion purchase of NBCUniversal, operator of networks like NBC, Bravo and USA, which was completed in March 2013.
New York state regulators on Monday also said will conduct a review of the merger between Time Warner Cable and Comcast to determine whether the union is in the best interest of the state's customers.
• Information from the Associated Press was used in this report.