The Google owner, Alphabet, has dropped its pledge not to use artificial intelligence for purposes such as developing weapons and surveillance tools.

The US technology company said on Tuesday, just before it reported lower-than-forecast earnings, that it had updated its ethical guidelines around AI, and they no longer referred to not pursuing technologies that could “cause or are likely to cause overall harm”.

Google’s AI head, Demis Hassabis, said the guidelines were being overhauled in a changing world and that AI should protect “national security”.

In a blogpost defending the move, Hassabis and the company’s senior vice-president for technology and society, James Manyika, wrote that as global competition for AI leadership increased, the company believed “democracies should lead in AI development” that was guided by “freedom, equality, and respect for human rights”.

They added: “We believe that companies, governments, and organisations sharing these values should work together to create AI that protects people, promotes global growth, and supports national security.”

Google’s motto when it first floated was “don’t be evil”, although this was later downgraded in 2009 to a “mantra” and was not included in the code of ethics of Alphabet when the parent company was created in 2015.

The rapid growth of AI has prompted a debate about how the new technology should be governed, and how to guard against its risks.

The British computer scientist Stuart Russell has warned of the dangers of developing autonomous weapon systems, and argued for a system of global control, speaking in a Reith lecture on the BBC.

The Google blogpost argued that since the company first published its AI principles in 2018, the technology had evolved rapidly. “Billions of people are using AI in their everyday lives. AI has become a general-purpose technology, and a platform which countless organisations and individuals use to build applications,” Hassabis and Manyika wrote.

“It has moved from a niche research topic in the lab to a technology that is becoming as pervasive as mobile phones and the internet itself; one with numerous beneficial uses for society and people around the world, supported by a vibrant AI ecosystem of developers.”

Alphabet’s shares fell by 8% when Wall Street opened. Tuesday’s report showed that the company made $96.5bn (£77bn) in revenues, slightly below analysts’ expectations of $96.67bn, because of slower growth in its cloud business. Google Cloud trails behind Amazon and Microsoft.

Evelyn Mitchell-Wolf, a senior analyst at eMarketer, said: “Cloud’s disappointing results suggest that AI-powered momentum might be beginning to wane just as Google’s closed model strategy is called into question by DeepSeek.”

Alphabet said it planned to spend $75bn on capital expenditure in the next year, largely to build out its AI capabilities and infrastructure.