The US is preparing to sue Android after it has blocked some popular file managers app users from accessing their data

US prosecutors have begun investigating whether Apple and Google infringe patents that Google has issued on file manager Android.US Attorney General Eric Holder has said Apple and others may be liable for infringing the Android operating system in several ways.

He said the US was also preparing to file a lawsuit.

The case is one of several cases that could be brought against Google and Apple over the past year in the US and Europe.

Google and Apple are facing lawsuits over their respective Android operating systems.

The two companies have faced intense pressure to remove unwanted software from Android devices in recent months.