BEIJING: The New York Times says Chinese hackers repeatedly penetrated its computer networks over the past four months, stealing reporters' passwords and hunting for files on an investigation into the wealth amassed by the family of one of China's leaders.

In a report released late Wednesday, the Times said security experts hired to plug the breach tracked the attacks to China, in some cases computers identified with the Chinese military.

The attacks coincided with a Times' investigation into how the family and relatives of Premier Wen Jiabao built a fortune worth more than $2 billion. The report says no Times' customer data was compromised but that the passwords for all employees were stolen.

Security experts say China carries out a widespread cyber-spying operation to steal secrets and intimidate critics.