Chinese hackers have resumed attacks on America three months after hackers, who worked for a cyber unit of China's People's Liberation Army, went silent amid evidence that they had stolen data from scores of American companies and government agencies.
The hackers appear to have resumed their attacks using different techniques, according to computer industry security experts and American officials.
According to the New York Times, Unit 61398, whose well-guarded 12-story white headquarters on the edges of Shanghai became the symbol of Chinese cyber power, is back in business, according to American officials and security companies.
It is not clear precisely who has been affected by the latest attacks.
Mandiant, a private security company that helps companies and government agencies defend themselves from hackers, said the attacks had resumed but would not identify the targets, citing agreements with its clients.
The hackers were behind scores of thefts of intellectual property and government documents over the past five years, according to a report by Mandiant in February that was confirmed by American officials.
According to the report, they have stolen product blueprints, manufacturing plans, clinical trial results, pricing documents, negotiation strategies and other proprietary information from more than 100 of Mandiant's clients, predominantly in the United States.
Mandiant said that the Chinese hackers had stopped their attacks after they were exposed in February and removed their spying tools from the organizations they had infiltrated.
It added that over the past two months, they have gradually started attacking the same victims from new servers.
