Owners of iPhones, iPads and computers are affected by a processor flaw which makes them vulnerable to hackers.

Apple is urging its customers to only download software from trusted sources.

The security vulnerabilities are known as Meltdown and Spectre.

This flaw was discovered by Google and academic institutions in 2016 and was subsequently kept secret.

There is no evidence that hackers have yet exploited this flaw, although companies including Microsoft have been working to provide urgent fixes.

An Apple statement said: "Security researchers have recently uncovered security issues known by two names, Meltdown and Spectre.

"These issues apply to all modern processors and affect nearly all computing devices and operating systems. All Mac systems and iOS devices are affected, but there are no known exploits impacting customers at this time.

"Since exploiting many of these issues requires a malicious app to be loaded on your Mac or iOS device, we recommend downloading software only from trusted sources such as the App Store."