Apple CEO Tim Cook has called on business news site Bloomberg to retract a story alleging Chinese spyware had been implanted in Apple devices.

The Bloomberg story said malicious chips had been built into servers manufactured in China and used in Apple products and devices made by other manufacturers, including Amazon.

Cook told news site Buzzfeed that Bloomberg needs to do that right thing and retract the story, which Apple and Amazon have both denied.

Despite mounting pressure, Bloomberg is standing by its report, which it says is the result of more than a year of reporting, during which it conducted more than 100 interviews.