(CNN Business) Staffers at some of America's best-known newspapers are wondering whether their systems were the victim of a foreign cyberattack.

Several papers, including the Los Angeles Times and The San Diego Union-Tribune, suffered printing and distribution delays as a result of the incident.

Some reporters chuckled at the irony of a digital bug interrupting printed papers. But there is also real concern about the effectiveness of the attack.

Tribune Publishing said "malware" was detected on its servers Friday. The Union-Tribune, which also called it a "virus," said most subscribers were left without a Saturday morning paper as a result.

The incident affected other newspapers in other ways. At The Baltimore Sun, for example, the usual comics and puzzles were not included in Saturday's print edition, the paper tweeted.

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