Representatives of the Federal Bureau of Investigation were not immediately available for comment.
"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 published by the Chicago Tribune.
The Chicago Tribune was among the publications targeted in the attack.
She declined to provide specifics on the disruptions, but the company properties include The Chicago Tribune, Baltimore Sun, Annapolis Capital-Gazette, Hartford Courant, New York Daily News, Orlando Sentinel and Fort Lauderdale Sun-Sentinel. We apologize for any inconvenience and thank our readers and advertising partners for their patience as we investigate the situation.More news: John Kelly Frequently Told People Trump Not Up to Job of President
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The Tribune Publishing spokeswoman also said "there is no evidence that customer credit card information or personally identifiable information has been compromised".
People pass the Los Angeles Times office in Los Angeles, California, in July 2018. The technology housed at the Los Angeles Times has been able to make some major strides in fixing the problem as it now stands.
"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 attack seemed to have begun late on Thursday night and by Friday had spread to crucial areas needed to publish the paper.
The cyberattack was able to cripple software systems responsible for storing news stories, photos and all of the administrative information needed to get the papers up and out of the printing facility. We need the plates to start the presses. Inc., said it was also affected. There was no ransom demand made, the source said.