New Delhi: Facebook on Thursday admitted that 5.62 lakh people in India had been "potentially affected" by the global data leak, while the government indicated it would act against the social media giant after receiving a response to the questionnaire it had sent to UK-based Cambridge Analytica.

Cambridge Analytica has been in the eye of the storm ater being accused of illegally mining personal information on millions of Facebook users to help political campaigns and influence elections in several countries, including India.

Officials said the government had received a reply from Facebook acknowledging that data on Indian users may have been compromised, and added that this made it all the more important to wait for Cambridge Analytica's response.

Cambridge Analytica has sought an additional week to send its responses to the government, pushing back the original deadline to April 7.

Facebook admitted on Wednesday that data on about 87 million people - mostly in the US - may have been improperly shared with Cambridge Analytica.

The social media giant said that 335 people in India were directly affected after installing a personality quiz app, "thisismydigitallife". The app was operated on the Facebook platform by a UK-based company, Global Science Research (GSR).

Another 562,120 people were potentially affected as friends of those users.

"This yields a total of 562,455 potentially affected people in India, which is 0.6 per cent of the global number of potentially affected people," a Facebook spokesperson said.

"Cambridge Analytica's 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 said in a statement.

The company said it was "investigating" the specific number of people whose information had been accessed, including those in India. It also emphasised that Cambridge Analytica's use of such data lacked its consent.

Facebook has over 20 crore users in the country, and the government had last month sent notices to both Facebook and Cambridge Analytica on the data breach.

Facebook's data breach scandal has sparked a furore in the country, with IT minister Ravi Shankar Prasad 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.

Facebook said it was not known exactly what kind of data had been siphoned off and stored or what the two involved companies - GSR and Cambridge Analytica - had done with that data.

Facebook has admitted that it is investigating whether any other app has similarly violated the privacy of users.

On April 9, Facebook said, it would show people a link at the top of their News Feed so they can see which apps they use and the information they have shared with those apps. It will also tell people whether information on them may have been improperly shared with Analytica.