NEW YORK — Threats of violence against movie theaters. Canceled showings of “The Interview.” Leaks of thousands more private emails. Lawsuits by former employees that could cost tens of millions in damages.

The fallout from the hack that began four weeks ago exploded Tuesday after the shadowy group calling themselves Guardians of Peace escalated their attack beyond corporate espionage and threatened moviegoers with violence reminiscent of the terrorist attacks of Sept. 11, 2001.

The Department of Homeland Security said there was “no credible intelligence to indicate an active plot against movie theaters,” but noted it was still analyzing messages from the group, dubbed GOP. The warning did prompt law enforcement in New York and Los Angeles to address measures to ramp up security.

Those security fears spurred Sony to allow theater chains to cancel showings of the Seth Rogen and James Franco comedy “The Interview,” that has been a focus of the hackers’ mission to bring down Sony. Carmike Cinemas, which operates 247 theaters across the country, was the first to cancel its planned showings of the film, according to The Hollywood Reporter. It remains to be seen if other chains will follow suit.

TROVE OF DATA RELEASED

GOP also released a trove of data files including 32,000 emails to and from Sony Entertainment CEO Michael Lynton in what it called the beginning of a “Christmas gift.”

And Sony workers have filed lawsuits alleging the Culver City, California, company was negligent. Social Security numbers, salary information and medical records were stolen.

In “The Interview,” Rogen and Franco star as television journalists involved in a CIA plot to assassinate North Korean leader Kim Jong Un. Speculation about a North Korean link to the Sony hacking has centered on that country’s angry denunciation of the film. Over the summer, North Korea warned that the film’s release would be an “act of war that we will never tolerate.” It said the U.S. will face “merciless” retaliation.

The film’s New York premiere is scheduled for Thursday at Manhattan’s Landmark Sunshine, and it is expected to hit theaters nationwide on Christmas Day. It premiered in Los Angeles last week.

But on Tuesday Rogen and Franco pulled out of all media appearances, canceling a Buzzfeed Q&A and Rogen’s planned guest spot Thursday on “Late Night With Seth Meyers.” A representative for Rogen said he had no comment. A spokeswoman for Franco didn’t respond to queries Tuesday.

The FBI said it is aware of the GOP’s threats and “continues to work collaboratively with our partners to investigate this matter.” FBI director James Comey last week said that investigators are still trying to determine who is responsible for the hack.

CYBER OR PHYSICAL ATTACK?

The New York Police Department, after coordinating with the FBI and Sony, plans to beef up security at the Manhattan premiere, said John Miller, the NYPD’s top counterterrorism official.

“Having read through the threat material myself, it’s actually not crystal clear whether it’s a cyber response that they are threatening or whether it’s a physical attack,” Miller said. “That’s why we’re continuing to evaluate the language of it, and also the source of it. I think our primary posture is going to be is going to have a police presence and a response capability that will reassure people who may have heard about this and have concerns.”

Following a commission meeting earlier Tuesday, Los Angeles Police Chief Charlie Beck said his department takes the hackers’ threats “very seriously” and will be taking extra precautions during the holidays at theaters.

The National Association of Theatre Owners had no comment on the developing situation. Neither Sony nor representatives from individual theater chains, including Carmike, responded to requests for comment.

Since the hack surfaced late last month, everything from financial figures to salacious emails between top Sony executives has been dumped online.