Image copyright Steve Jennings Image caption Top Google executive Diane Greene told staff on Friday there would be no renewal of the contract (file pic)

Google will not renew a contract to do artificial intelligence work for the US Pentagon, company sources say.

The decision follows strong opposition in the technology giant's workforce.

A number of Google employees resigned and thousands of others signed a protest petition against taking part in the Pentagon project, known as Maven.

They feared it was the first step towards using artificial intelligence for lethal purposes. There has been no official statement from Google.

According to company sources, top executive Diane Greene told staff on Friday there would be no follow-up after the current contract expired next March.

But Kate Conger, a journalist for the technology news website Gizmodo, told the BBC that Google had not cancelled Project Maven and did not appear to have ruled out future work with the military.

The contract is reported to be worth less than $10m (£7.5m) to Google but could potentially lead to more extensive cooperation with the Pentagon.

Project Maven involves using machine learning and engineering talent to distinguish people and objects in drone videos.

In April up to 4,000 Google employees signed an open letter saying that by its involvement in the project the internet giant was putting users' trust at risk, as well as ignoring its "moral and ethical responsibility".

A report by Gizmodo said that senior leadership at the company was deeply conflicted about the effects of the partnership with the Pentagon.

Internal emails suggested that executives saw the contract as a huge opportunity while being concerned about how the company's involvement would be perceived, Gizmodo said.