(Reuters) - Angry Birds maker Rovio said on Tuesday it had bought Futuremark Games Studio, the gaming arm of Finnish benchmarking software firm Futuremark, for an undisclosed sum.

The acquisition of the studio - known for its space-games Unstoppable Gorg and Shattered Horizon - comes a week after Rovio launched its latest Angry Birds Space game.

Its new game was downloaded more than 10 million times within first three days, topping the sales charts on Apple platforms in 104 countries.

Rovio, the Finnish company behind the world's most downloaded mobile game, has been valued at up to $9 billion little more than two years after it first launched Angry Birds for Apple's iPhone.

Angry Birds games have been downloaded more than 700 million times and are the fastest-growing games on Facebook.

(Reporting by Tarmo Virki; Editing by David Holmes)