(Reuters) - AI video startup Runway said on Thursday it had raised $308 million in a new funding round, led by private equity firm General Atlantic, to expand its new media ecosystem.

The latest funding round valued the New York-based company at over $3 billion, Bloomberg reported, citing people familiar with the matter.

Runway, however, declined to comment in reference to the valuation.

With the latest fundraise, the startup plans to develop AI research for new media focusing on its AI film and animation studio using world simulators.

A world model is an AI system that builds an internal representation of an environment, and uses it to simulate future events within that environment.

The round also saw participation from SoftBank Group, Nvidia, Fidelity Management & Research Company and Baillie Gifford.

Runway, which offers software that allows users to create videos by using text prompts or images, signed a deal with Lionsgate last September to create a customized video generation model to help "filmmakers, directors and other creative talent augment their work".