A sample of 750,000 entries posted online by the hacker showed citizens’ names, mobile phone numbers, national ID numbers, addresses, birthdays and police reports they had filed.

AFP and cybersecurity experts have verified some of the citizen data in the sample as authentic, but the scope of the entire database is hard to determine.

Advertised on a forum late last month but only picked up by cybersecurity experts this week, the 23-terabyte database — which the hacker claims contains the records of a billion Chinese citizens — is being sold for 10 bitcoin (approximately $200,000).