Facebook Chief Executive Mark Zuckerberg, who is in India for the Internet.org Summit, said the company is focusing on getting more people to use the service.

"Over the long term, I think there are pretty clear models for building products around messaging products. You can see that through examples like some of the Chinese messaging products like Tencent. Wechat has been very successful.

"We have different ideas about what we can do but for the near future, I mean the next few years, we are really focused on connecting more people, to get them to use our service," Zuckerberg said.

WhatsApp has over 600 million using the service every month. It works across different types of phones without advertising. The app charges 99 cents as an annual subscription fee, which is waived off for the first year.

According to reports, Facebook's final WhatsApp acquisition price tag has risen by an additional USD 3 billion to roughly USD 22 billion because of the increased value of Facebook's stock in recent months.

In February this year, Facebook announced its largest-ever acquisition with the transaction involving USD 12 billion worth of Facebook shares, USD 4 billion in cash and USD 3 billion in restricted stock units.