Facebook data of over 5.62 lakh Indians may have been compromised as the UK-based Cambridge Analytica pilfered them through an app, the US social media giant said on Thursday.
The government, on its part, said its action in the data leak case will depend on the response Cambridge Analytica submits to its notice.
Under fire globally for allowing the data breach, Facebook sent a formal response to the questions the Indian government had raised on the issue.
A Facebook spokesperson said privileged data of users who had downloaded the app called thisisyourdigitallife, developed by Dr Aleksandr Kogan, may have been compromised.
There are about 200 million Facebook users in the country. Of them, "only 335 people" in India were directly affected through the installation of the app, while another 5,62,120 people were "potentially affected" as friends of those users, the spokesperson said.
"Cambridge Analyticas acquisition of Facebook data through the app developed by Dr Aleksandr Kogan and his company Global Science Research Limited (GSR) happened without our authorisation and was an explicit violation of our Platform policies," a Facebook spokesperson explained.
A government source confirmed that Facebooks reply has been received, and added that the same is being examined. However, a final call in the matter will be taken only after Cambridge Analytica sends its response.
Cambridge Analytica, the data mining firm at the centre of the controversy, has time till April 7 to send its response to the government.
In its response, Facebook has asserted that it had "at no time" agreed to Cambridge Analyticas use of any user data - including those in India.
Also on April 9, Facebook will provide a link at the top of users News Feed, offering information on apps that people use and the data they have shared with such apps.
It will also tell people if their information may have been improperly shared with Analytica.
Facebook said the total number of potentially impacted users (5,62,455 people) is 0.6 per cent of the global number of potentially affected people.
The profiling app was installed by 335 people in India, which is estimated to be 0.1 per cent of the apps total worldwide installs.
Facebooks response comes a day after it said data of about 87 million people - mostly in the US - may have been improperly shared with Cambridge Analytica. This is far higher than the original estimate of 50 million users being affected by the global data breach.
Cambridge Analytica has been accused of harvesting personal information of millions of Facebook users illegally to influence polls in several countries.
Facebook had said it is "investigating" the specific number of people whose information was accessed, including those in India. The outrage - including online campaigns like #deletefacebook- forced the company to issue a public apology.
Facebooks data breach scandal also sparked an outrage in India with IT Minister Ravi Shankar Prasad last month warning the firm of "stringent" action for any attempt to influence polls through data theft and threatening to summon Facebook CEO Mark Zuckerberg, if needed.