U.S. security agencies are investigating a threat against theaters planning to show the Sony movie that allegedly spearheaded the company's massive hack, two officials said, but so far they have seen no real sign of an active plot.

A hacking group yesterday published what appear to be more internal emails and promised a "bitter fate" for those who went to see "The Interview" following a cyber attack that severely damaged the movie studio's network. An official at the U.S. Department of Homeland Security and another U.S. security official cast doubt on the threat.

"At this time there is no credible intelligence to indicate an active plot against movie theaters within the United States," the DHS official said.

Sony is already reeling from the disclosures in documents released by the hackers, which have publicly exposed internal discussions important to the company's future.

"The Interview," starring James Franco and Seth Rogen, is set to premiere in New York tomorrow at the Sunshine Theater and open to general audiences on Christmas. Landmark didn't return calls for comment by press time.

John Miller, the NYPD's deputy commissioner for counterterrorism and intelligence, told reporters that police are evaluating the threat seriously.

"I think our primary posture is going to be to have a police presence and a response capability that will reassure people who may have heard about this and have concerns," he said.

BuzzFeed reported that Franco and Rogen had canceled all planned media appearances Tuesday, the day they were scheduled to appear at a BuzzFeed event. Representatives for the actors did not immediately respond to requests for comment.

A Sony spokeswoman had no immediate comment on the threat.

The newest file published Tuesday appeared to be emails from Sony studio chief Michael Lynton. Several rounds of leaks have prompted apologies for disparaging remarks executives made about celebrities.