WhatsApp has refuted Central government's allegation that it had kept the snooping on Indian citizens a secret.

Facebook-owned mobile messaging service on October end informed a few Indian journalists and human rights activists that they were among the 1,400 people globally who were spied upon by unnamed entities using an Israeli spyware dubbed Pegasus.

The Centre, which is now under fire from journalists and the Opposition, on Friday demanded a clarification from WhatsApp and questioned why it had kept this information hidden from the Indian authorities despite recent meetings with the company CEO.

In a statement on what is now being known as snoopgate, WhatsApp claimed that it had informed the Indian government about the 'security issue' in May.

"Our highest priority is the privacy and security of WhatsApp users. In May, we quickly resolved a security issue and notified relevant Indian and international government authorities," the WhatsApp statement said.

The messaging service added that since the attack, the company has "worked to identify targeted users to ask the courts to hold the international spyware firm known as the NSO Group accountable."

"We agree with the government of India it's critical that together we do all we can to protect users from hackers attempting to weaken security. WhatsApp remains committed to the protection of all user messages through the product we provide," it said.

WhatsApp has accused an Israeli surveillance firm, NSO Group, of helping unnamed entities' spies to hack into phones of roughly 1,400 users across the globe.

These users span across four continents and include diplomats, political dissidents, journalists and senior government officials. However, it did not say on whose behest the phones of journalists and activists across the world were targeted.

WhatsApp has said that it will sue NSO Group in the international court.