The New York Times says Chinese hackers have been attacking their computers for the last four months.
The Times reports the hackers stole reporters' passwords and searched files connected to the paper's investigation of a Chinese family's $2 billion fortune.
The paper says security experts hired to plug the breach tracked the attacks to China, in some cases computers identified with the Chinese military.
The Times says customer data was not compromised.
A Chinese foreign ministry spokesman called the Times' report groundless.