Large US newspapers have been hit by an electronic attack that has been the latest in print and distribution across the United States, and details are not immediately clear.
The Los Angeles Times said Saturday's attack appeared to have originated outside the United States, while a spokeswoman for the Department of Homeland Security said the ministry was working to assess what had happened.
The electronic attack was blocked by the printing and distribution of the Los Angeles Times, the Chicago Tribune, and the Baltimore Sun. Los Angeles Times said copies of the US West Coast from the Wall Street Journal and the New York Times were also affected by the attack because they were printed on a common platform in Los Angeles.
The newspaper Tribune, which publishes a number of newspapers, said it detected malicious software on Friday and damaged printing and production systems in all its facilities.
"We are aware of reports of a possible cyber attack affecting several news organizations and we are working with our partners in government and industry to better understand the situation," a spokeswoman for the Department of Homeland Security said in a statement.