Some shareholders are threatening to reject the proposed combination of Verizon and MCI in a proxy vote.
European regulators have already forced Time Warner to pull back from a proposed combination of its Warner Music unit and the EMI Group of Britain.
He noted that the proposed combination of Delta Air Lines and Northwest Airlines, announced on Monday, would create "a formidable competitor".
The dispute helped galvanize critics of the proposed combination of AOL and Time Warner as regulators were starting to look into the deal.
The combined company, to be called Vivendi Universal, creates an entertainment-telecommunications giant second in size only to the proposed combination of America Online and Time Warner Inc.
Concerns about fair access to TV programming dominated the first day on Thursday of Congressional hearings on the proposed combination of Comcast and NBC Universal.
United hopes to merge with another airline — Continental Airlines and US Airways are leading candidates — in order to compete against the proposed combination of Delta Air Lines and Northwest Airlines.
One board member, Anne Ellis, resigned last week, saying that the proposed combination of the two channels would result in Long Island residents' being shortchanged in programming related to their community.
Sources close to the proposed combination of Britain's largest defence contractor and the owner of Airbus admitted that both companies are likely to seek an extension to the deadline.
If Procter & Gamble combined all three pharmaceutical businesses, the new drug business would be the second-largest prescription drug seller in the United States, behind the proposed combination of Glaxo Wellcome and SmithKline Beecham.
Further consolidation in the industry is the subject of much speculation, after the proposed combination of Delta and Northwest.In a long-awaited decision Time Warner said it would spin off its cable-system business.
