Dec. 30 (UPI) -- A suspected malware attack affected publication of several newspapers across the United States.
Affected Saturday were those owned by the Tribune Publishing and other publications printed at its plants.
The print edition of the company's flagship newspaper, Chicago Tribune, was published Saturday without paid death notices and classified ads. In other markets, delivery was delayed or the Saturday edition was included with the Sunday one.
And in some cases, their phones were disrupted, including not being able to take calls from subscribers wanting to know why they hadn't received their newspaper.
"This issue has affected the timeliness and in some cases the completeness of our printed newspapers," Tribune Publishing spokeswoman Marisa Kollias said in a statement. "Our websites and mobile applications however, have not been impacted."
Jeff Light, the editor and publisher of the San Diego Union Tribune, said the virus started affecting the newspapers' systems Thursday and became a critical problem late Friday.
The Union-Tribune, a former Tribune Publishing newspaper along with the Los Angeles Times, still uses the company's production software.
The Los Angeles Times, which print editions of both of its papers, also had problems printing The New York Times and The Wall Street Journal.
"Papers that should have arrived in San Diego around 3 a.m. to 4 a.m. instead arrived at 7 a.m. and 8 a.m.," said Light, who estimated 85 percent to 90 percent of the Saturday edition of the Union-Tribune did not reach subscribers on Saturday morning.
The newspaper relies on independent contractors to deliver the paper to neighborhoods, and many of those people were not available later Saturday to do the deliveries.
The L.A. Times, citing a "source with knowledge of the situation," reported the cyberattack "appears to have originated from outside the United States."
The company is investigating the malware attack and "making progress" to resolve issues with its newspaper production, Kollias said. The attack was reported to the FBI.
On Thursday night, editors were unable tried to send pages, via digital files, to the plate-making facility. Certain computers had been infected.
The Los Angeles Times reported the attack appears to be in the form of "Ryuk" ransomware, which are "highly targeted, well-resourced and planned," according to an August advisory by the U.S. Department of Health and Human Services' cybersecurity program.
Formerly known as Tronc, Tribune Publishing also owns the South Florida Sun Sentinel; the Orlando Sentinel; The Baltimore Sun; the Hartford Courant; the New York Daily News;the Capital Gazette in Annapolis, Md.; The Morning Call in Allentown, Pa.; the Daily Press in Newport News, Va.; and The Virginian-Pilot in Norfolk, Va. Tribune also produces suburban newspapers in its markets.
The Sun Sentinel said in a statement published on its website that the Saturday edition would be delivered along with the Sunday edition. Also printed at its Deerfield Beach printing plant are The Palm Beach Post, Palm Beach Daily News and The New York Times. Some editions of the Post were delivered Saturday.
In Baltimore, usual comics and puzzles were not included in Saturday's print edition, the paper said.