The announcement marks a strategic shift by OpenAI, which until now has been a fierce defender of closed, proprietary models that do not allow developers to modify the basic technology to make AI more adapted to their goals.

OpenAI and defenders of closed models -- which include Google -- have often decried open models as more risky and vulnerable to nefarious uses by bad actors or foreign adversaries.

OpenAI's embrace of closed models has also been a bone of contention in its battles with former investor Elon Musk, the world's wealthiest person, who has called on OpenAI to honor the spirit of the company's name and "return to the open-source, safety-focused force for good it once was."

Putting pressure on OpenAI, many large companies and governments have proved reluctant to build their AI products or services on models they have no control over, especially when data security is a concern.

The core selling point of Meta's family of Llama models or DeepSeek's models is addressing these worries by letting companies download their models and have far greater control to modify the technology for their own purposes and keep control of their data.

Meta CEO Mark Zuckerberg said earlier this month that Llama hit one billion downloads, while the release of DeepSeek's lower cost R1 model in January rocked the world of artificial intelligence.

"We've been thinking about this for a long time but other priorities took precedence. Now it feels important to do," OpenAI's chief executive Sam Altman said on X.

As it builds its new model, the company plans to gather developer feedback through a series of events starting in San Francisco in the coming weeks, followed by sessions in Europe and Asia-Pacific regions.

The announcement came as OpenAI has been riding on the success of its latest image-generation features in ChatGPT, the world-leading AI app and chatbot.

Altman posted on Monday that the tool helped add "one million users" in one hour.

That claim came days after Altman said the new image features were so popular that they were melting the OpenAI graphics processing units that power the AI due to heavy use.

The flurry of announcements comes as OpenAI is reportedly finalizing a $40 billion funding round led by Japan's SoftBank Group that would be the biggest capital-raising session ever for a startup.