BRUSSELS - EU lawmakers and governments were still wrangling on Thursday over several key issues on landmark rules governing artificial intelligence, two sources familiar with the matter said, as talks extended through the night into a second day.

The two sides agreed to a provisional deal on how to regulate fast-growing generative AI systems such as ChatGPT in the early hours of Thursday, overcoming one of the biggest stumbling blocks to a final deal, a source told Reuters.

The other one, the use of AI in biometric surveillance, and source code access were yet to be debated after 17 hours of talks, two sources familiar with the matter said. They declined to be identified because the talks are confidential.

The Council of the European Union on Thursday postponed a press conference scheduled for 0700 GMT until further notice as negotiations continue. The discussion between EU governments and lawmakers started at 1400 GMT on Wednesday.

Amid tense debates, and frustration over a broken drinks machine, one of the sources said delegates ran out of food and coffee at about 0200 GMT.

EU countries and lawmakers have been trying to finalise details of the draft rules proposed by the European Commission two years ago but have struggled to keep up with the rapidly evolving technology. That made a consensus hard to achieve.

The new law could become the blueprint for other governments as countries seek to craft rules for their own AI industry, providing an alternative to the U.S.' light-touch approach and China's interim rules.

Agreeing provisional terms on foundation models, the generative AI such as OpenAI which trains on large sets of data to perform various tasks, would be a big step.

The details of what was agreed were not clear. A fourth source said there were still aspects to be thrashed out.

But a late proposal by France, Germany and Italy that makers of generative AI models should self-regulate had added a point of discord. Such a move however would benefit France-based AI company Mistral and Germany's Aleph Alpha.

On biometric surveillance, EU lawmakers want to ban the use of AI, but governments have pushed for an exception for national security, defence and military purposes.

(Reporting by Foo Yun Chee; Writing by Josephine Mason; Editing by Kim Coghill, Matt Scuffham, Jan Harvey and Alexander Smith)