The lawsuit is expected to be filed in the coming weeks, the sources said.

It was not immediately clear which other states would ​join the lawsuit, which would mark the boldest move yet by the states in their effort to be at the forefront ​of US antitrust enforcement.

California Attorney General Rob Bonta on Thursday criticised what he called President ⁠Donald Trump’s “abdication” of federal antitrust agencies with more resources than the state governments.

Bonta, a Democrat, has led the charge among states concerned ​about the deal, promising a probe soon after Paramount announced it would acquire Warner Bros, after beating a bid by streaming giant ​Netflix.

On Friday, a spokesperson for Bonta’s office said California’s investigation remains active but declined to comment further.

Shares of Warner Bros fell after Reuters first reported the news, and were down 3.6% on Friday afternoon.

Paramount shares added to losses and were down 6.7%.

Not all lawsuits seeking to block mergers succeed. ​

But they can delay the consummation of deals by months if a judge issues an order pausing the merger while ​the case plays out.

Paramount has agreed to pay shareholders a fee starting in October if the deal has not closed.

Those fees add ‌up ⁠to around $6.9 million per day, the company said recently.

Analysts have said Paramount’s political connections and other factors should give it an easier road to regulatory clearance from federal antitrust watchdogs in the US.

Paramount CEO David Ellison’s father, billionaire Oracle co-founder Larry Ellison, has cultivated ties with Trump.

The US Department of Justice is likely to decide on the deal soon, according to a ​source familiar with the matter.

The ​DOJ sent subpoenas in late ⁠March seeking information on how the merger would affect studio output, content rights, streaming competition and movie theatres.

A Paramount spokesperson said the deal would bring greater competition, and opposing it “means giving ​entrenched incumbents like Netflix an advantage they do not deserve.”

“We will continue to fight against any ​attempt to derail ⁠a deal that plainly benefits consumers, creators, and the industry as a whole,” the spokesperson said.

Paramount has pledged to maintain both studios and produce a minimum of 30 theatrical films annually after the deal closes.

The deal, which would combine two of Hollywood’s four ⁠major studios, ​has drawn criticism from actors, writers and others in Hollywood who fear job losses.

Theatre ​owners also oppose the combination of the storied Warner Bros movie studio, maker of the “Harry Potter” and “Superman” films, with Paramount Pictures, arguing it will give cinemas fewer ​movies to choose from, eroding competition.