Donald Trump has said he will be "involved" in the decision on whether Netflix should be allowed to buy Warner Bros, as the $72bn (£54bn) deal attracts a media industry backlash.
The US president acknowledged in remarks to reporters there "could be a problem", acknowledging concerns over the streaming giant's market dominance.
Crucially, he did not say where he stood on the issue.
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It was revealed on Friday that Netflix, already the world's biggest streaming service by market share, had agreed to buy Warner Bros Discovery's TV, film studios and HBO Max streaming division.
The deal aims to complete late next year after the Discovery element of the business, mainly legacy TV channels showing cartoons, news and sport, has been spun off.
But the deal has attracted cross-party criticism on competition grounds, and there is also opposition in Hollywood.
The Writers Guild of America said: "The world's largest streaming company swallowing one of its biggest competitors is what antitrust laws were designed to prevent.
"The outcome would eliminate jobs, push down wages, worsen conditions for all entertainment workers, raise prices for consumers, and reduce the volume and diversity of content for all viewers."
Republican Senator, Roger Marshall, said in a statement: "Netflix's attempt to buy Warner Bros would be the largest media takeover in history - and it raises serious red flags for consumers, creators, movie theaters, and local businesses alike.
"One company should not have full vertical control of the content and the distribution pipeline that delivers it. And combining two of the largest streaming platforms is a textbook horizontal Antitrust problem.
"Prices, choice, and creative freedom are at stake. Regulators need to take a hard look at this deal, and realize how harmful it would be for consumers and Western society."
Paramount Skydance and Comcast, the parent company of Sky News, were two other bidders in the auction process that preceded the announcement.
The Reuters news agency, citing information from sources, said their bids were rejected in favour of Netflix for different reasons.
Paramount's was seen as having funding concerns, they said, while Comcast's was deemed not to offer so many earlier benefits.
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Paramount is run by David Ellison, the son of the Oracle tech billionaire Larry Ellison, who is a close ally of Mr Trump.
The president said of the Netflix deal's path to regulatory clearance: "I'll be involved in that decision".
On the likely opposition to the deal. he added: "That's going to be for some economists to tell. But it is a big market share. There's no question it could be a problem."
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