The U.S. is ready to blame North Korea for the crippling hack attack at Sony Pictures, as the studio said Wednesday it would cancel next week's planned release of its controversial comedy "The Interview."

U.S. investigators say an announcement pinning the blame on hackers working for the Pyongyang regime could come as soon as Thursday.

Because of the North Korean regime's tight control of the Internet in the reclusive country, U.S. officials believe the hack was ordered directly by the country's leadership.

North Korea experts say the country has spent its scarce resources on building up a unit called "Bureau 121" to carry out cyber attacks.

Earlier Wednesday, Sony pulled the film, which depicts the assassination of North Korea's leader, following a threat that people should avoid going to theaters where "The Interview" is playing.

Related: Sony downplays possibility of video release of 'The Interview'

Sony didn't have much choice -- the country's major theater owners had virtually all said they had decided to postpone or cancel next week's screenings. Concerns about upholding freedom of artistic expression were countered by fears that families would heed the hackers' warning and bypass the box office for the remainder of the holiday season.

"In light of the decision by the majority of our exhibitors not to show the film "The Interview," we have decided not to move forward with the planned December 25 theatrical release," Sony said in its first statement on the matter.

"Sony Pictures has been the victim of an unprecedented criminal assault against our employees, our customers, and our business," the company said.

"We are deeply saddened at this brazen effort to suppress the distribution of a movie," the company added. "We stand by our filmmakers and their right to free expression and are extremely disappointed by this outcome."

Some prominent screenwriters and stars also expressed dismay and sadness about the outcome. "Today the U.S. succumbed to an unprecedented attack on our most cherished bedrock principle," Aaron Sorkin told The Los Angeles Times.

Judd Apatow called the theater owners' decisions "disgraceful:" "Will they pull any movie that gets an anonymous threat now?"

The comedy was scheduled to come out on Christmas Day.

Why Sony decided to cancel the film's release

According to sources with direct knowledge with the situation and statements by some of the companies, among the top chains that had decided to drop the movie were AMC Entertainment, Regal (RGC), Cinemark (CNK) and Carmike Cinemas (CKEC).

Several smaller chains, including Bow Tie Cinemas and Southern, had decided to do the same thing.

Bow Tie said in a statement that it was "saddened and angered" by the threats against the film. "It is our mission to ensure the safety and comfort of our guests and employees," it said.

Another chain, Cineplex, which is based in Canada, also said it would postpone its showings. P

"Cineplex takes seriously its commitment to the freedom of artistic expression, but we want to reassure our guests and staff that their safety and security is our number one priority," the company said. "We look forward to a time when this situation is resolved and those responsible are apprehended."

And Regal said it would "delay the opening" in its theaters, citing "the wavering support of the film 'The Interview' by Sony Pictures, as well as the ambiguous nature of any real or perceived security threats."

"The Interview" became controversial because its plot involves the attempted assassination of North Korean dictator Kim Jong-un.

CNN has learned that State Department officials had a discussion with Sony executives but they did not weigh in on the production.

Sony still trying to recover from the hacking

Sony Pictures has been devastated by the cyberattack that appears motivated by anger over the film. Analysts expect it will cost hundreds of millions of dollars for the company to recover.

The film's Los Angeles premiere went off without a hitch last week, but the New York premiere planned for Thursday was called off after the new threat on Tuesday.

The threat, which invoked the Sept. 11, 2001 terrorist attacks, received widespread press attention.

Related: New York cinema cancels premiere after threat

Mark Cuban, the co-owner of the Landmark theater where the premiere was scheduled, said it was scrapped because "the downside was too dramatic versus the upside."

"You can't go and enjoy a movie when, in the back of your mind, you're concerned that something's gonna happen," Cuban said in an interview. "And it just wasn't worth the risk."

One of the sources with direct knowledge of the situation described another consideration: "The possibility that people will avoid theaters altogether is the problem," the person said.

In other words, it's not just "The Interview" that could be hurt, it's other Christmas releases like Disney' (DIS)"Into The Woods" and Universal's "Unbroken."

On Wednesday, some inside and outside Hollywood voiced concerns that Sony and the theater owners had overreacted to a far-fetched terroristic scenario.

Daveed Gartenstein-Ross, a senior fellow at the Foundation for Defense of Democracies, said on CNN's "New Day" that "this is essentially a heckler's veto" of the film.

The FBI has been investigating the hack, and the U.S. Department of Homeland Security said Tuesday that "there is no credible intelligence to indicate an active plot against movie theaters within the United States."

The U.S. government has offered support to Sony in response to the hack, according to a statement from the White House National Security Council.

"The U.S. government is working tirelessly to bring the perpetrators of this attack to justice, and we are considering a range of options in weighing a potential response," according to the NSC statement. "We take very seriously any attempt to threaten or limit artists' freedom of speech or of expression."

Meanwhile, all the attention had caused some people to pledge to see the film.

Apatow had written on Twitter on Tuesday night, "I am not going to let a terrorist threat shut down freedom of speech. I am going to The Interview."

But now he can't see it in a theater. And Sony indicated Wednesday night that it had no plans to release the film digitally.

--CNN's Lorenza Brascia, Tom Kludt, Frank Pallotta, Molly Shiels, and Jimmy Carr contributed reporting.