The cyber attack on the Marriott hotel chain that collected personal details of some 500 million guests was the work of the Chinese hackers which also hacked health insurers and the security clearance files of millions more Americans, according to informed sources.
The hackers stole the personal information such as phone numbers, email address, and passport numbers along with the details pertaining to the health insurance and security clearance of the Marriott guests.
The hackers were suspected of working on behalf of the Ministry of State Security, the country's Communist-controlled civilian spy agency, the sources told The New York Times on Tuesday.
The Marriott database contains both the credit card information and passport data.
The hackers stole passport numbers of up to 327 million people - many of whom stayed at Sheraton, Westin and W hotels and at other Starwood-branded properties.
Marriott hotel group discovered a breach in its Starwood hotel reservation system back in September and it revealed the information to public last month.
But Marriott has not confirmed if it would pay to replace those passports, an undertaking that would cost tens of billions of dollars.
US President Donald Trump's administration is planning actions targeting China's trade, cyber and economic policies.
Reports last week indicated that the hacking tools and techniques used in the breach were similar to the ones that have been accredited to the Chinese hackers in the past.
The Marriott hacking is not expected to be part of the coming indictments.
China firmly opposes all forms of cyber attack and cracks down on it in accordance with the law.
If offered evidence, the relevant Chinese departments will carry out investigations according to the law.