Mobile messaging app WhatsApp on Tuesday said it has crossed the one billion user milestone globally with the addition of 100 million users in last five months.

"As of today, one billion people are using WhatsApp. That's nearly one in seven people on Earth who use WhatsApp each month to stay in touch with their loved ones, their friends and their family," WhatsApp said in a blog post.

In February 2014, WhatsApp was acquired by social networking site Facebook, its biggest buyout till date, for a whopping USD 19 billion.

In a post on Facebook, WhatsApp co-founder Jan Koum said 42 billion messages were sent, 1.6 billion photos and 250 million videos shared everyday on the platform.

Also, there are one billion groups on WhatsApp, he said.

Previously, WhatsApp has said its service has seen strong uptake, specially across developing nations such as Brazil, India and Russia.

"In India, more photos are sent using WhatsApp than in any other country in the world. As one of WhatsApp's largest countries, it's not surprising that the second highest number of groups are here," the company said.

WhatsApp competes with messaging apps like LINE, Viber and Hike in India.

Facebook chief Mark Zuckerberg also congratulated Koum and his team.

"WhatsApp's community has more than doubled since joining Facebook. We've added the ability for you to call loved ones far away. We've dropped the subscription fee and made WhatsApp completely free. Next, we're going to work to connect more people around the world and make it easier to communicate with businesses," he said.

Zuckerberg added that there are only a few services that connect more than a billion people and this milestone is an important step towards connecting the entire world.

Recently, WhatsApp had said it will stop charging USD 1 per year subscription fee to go completely free for its users across the world.

Also, it will not introduce any third-party ads for monetisation and is going to experiment with new models to stay ad-free, it had added.