NEW DELHI, March 28 (Xinhua) -- The Indian government has served a notice to leading social networking site Facebook over alleged leak of data of millions of users.

"The notice was served on Facebook by India's Ministry of Communications and Information Technology. The Ministry has given Facebook time till April 7 to file its response on the issue," sources said Wednesday.

In its notice, the ministry has sought replies to a set of questions, including if personal data of Indian voters was compromised by Cambridge Analytica, a global firm which is accused of manipulating social media information in many countries to influence voters for its clients.

Last week, the Indian government also slapped a notice on Cambridge Analytica and even threatened to initiate legal action if it failed to respond to the notice by March 31.

The Indian government also asked the main opposition Congress party to come clean on its "links" with Cambridge Analytica last Wednesday, citing media reports that it hired the data firm to run their campaign for 2019 general elections.

The Congress party has refuted the allegations, while both Cambridge Analytica and Facebook have denied any wrongdoing.