Denver ? Adolph Coors Co., the third-biggest brewer in the United States, and Canada’s Molson Inc. announced plans to merge Thursday in a $3.4 billion deal that would create a North American giant to compete against the world’s beermaking titans.

The combined company created by the deal, which was described as a merger of equals, would have annual revenues of about $6 billion and rank fifth in the world by brewing volume, the companies said.

It will be known as Molson Coors Brewing Co., and market brands like Coors Original and Coors Light, Molson Canadian, Keystone and Carling.

The deal would merge two family-led breweries both founded more than a century ago. Golden, Colo.-based Coors trails Anheuser-Busch and SABMiller in the U.S. brewing business, while Montreal-based Molson is neck-and-neck with Interbrew SA’s Labatt Brewing in Canada.

“I am very proud to see the company started by my great-grandfather more than 130 years ago combine with a company of Molson’s caliber and heritage,” said Coors chairman Peter H. Coors, who is running for the U.S. Senate in Colorado.

“This transaction allows us to create a stronger company in a consolidating global industry while preserving Molson’s rich heritage as North America’s oldest beer company and Canada’s leading brewer,” chairman Eric Molson said in a statement.

The deal is subject to regulatory and shareholder approval.

A former Molson executive could create a hitch in the plans. The Wall Street Journal reported Thursday that former Molson deputy chairman Ian Molson was expected to make an offer to acquire the company for as much as $4 billion. The offer would value the stock at 30 a share, which would create a premium of more than 30 percent of the stock price before the merger was announced — something the Coors offer lacks.

Ian Molson and Eric Molson, his cousin, have clashed about the brewery. Ian Molson resigned from the board in May over disagreements with his cousin.

The Ian Molson offer would come from a group of investors and a possible corporate partner, the Journal said, citing sources close to the situation.

Molson chief Daniel J. O’Neill declined to comment on the report, while Eric Molson said there was a good deal of support for the merger.

Molson shares rose 3 percent to $26.99 on the Toronto stock market Thursday, while Coors shares fell $1.54, or 2 percent, to $73.19 on the New York Stock Exchange.

Peter Coors, chairman of Adolph Coors Co., left, and Eric Molson, chairman of Molson Inc., shake hands at the start of a press conference. They announced a merger of the companies Thursday in New York.