Popular online game World Of Tanks, published by Wargaming.net, now has 5 million users globally.
The news comes as the game reaches its one year anniversary.
"We didn't expect World of Tanks would become this popular," said CEO Victor Kislyi.
"The game's success has given us confidence we needed to continue our expansion into the world of online wargames."
The game has around 172,000 players online at any one time, beating its total on January 23, which set a Guiness World Record at just 91,311.
Last week the company opened a new office in San Francisco.