Rupert Murdoch's media conglomerate 21st Century Fox said Wednesday it made a bid for rival Time Warner, but that no talks are ongoing after the bid was rejected.

The bid, which would have combined two of the world's biggest media-entertainment empires if allowed to proceed, was for $80 billion, a source familiar with the talks told AFP.

A statement from 21st Century Fox, said it "made a formal proposal to Time Warner last month to combine the two companies."

The source said that despite the rejection, Murdoch still wants a deal.

"He is determined to buy Time Warner," the source said.

The statement from 21st Century Fox, which came after a New York Times report about the offer, said the Time Warner board of directors "declined to pursue our proposal," and added that "we are not currently in any discussions with Time Warner."

The source familiar with the talks told AFP that Murdoch's group wanted to buy Time Warner and then spin off CNN, which is the cable news rival to his Fox News Channel.

The move comes amid a shifting media landscape after both conglomerates spun off their slow-growing publishing operations and established companies focusing on film, television and other high-growth segments.

Murdoch last year broke up his media empire into two firms -- 21st Century Fox and News Corp, which operates the Wall Street Journal, and newspapers in Britain and Australia.

Time Warner this year spun off its magazine unit Time Inc., which publishes its flagship news weekly and other titles including Sports Illustrated and People.

The deal between the two giants would combine the storied Hollywood studios of Time Warner and 20th Century Fox, and include Time Warner's big cable channels such as HBO and TBS that would join Murdoch's Fox sports and news channels.