US software specialist Oracle has launched a copyright and patent infringement lawsuit against Google, claiming that the search engine giant's mobile phone operating system uses elements of its technology.

The software company alleges Google infringed seven patents that fell under Oracle's control after it acquired rival Sun Microsystems in January.

Oracle claims that Google "knowingly" infringed its Java software, which is widely used by developers to write applications for different operating systems.

The legal action is the first example of Larry Ellison, the outspoken chief executive of Oracle who is also one of America's richest men, flexing his muscles on Java since it acquired Sun.

The suit will also be seen as a warning shot across the bows of Google.

The growing power of Google was illustrated by data from the research firm Gartner this week which revealed that global sales of Android have outstripped Apple's iPhone for the first time. The search giant only launched the operating system two years ago.

In a statement, Oracle said that Google had "knowingly, directly and repeatedly infringed Oracle's Java-related intellectual property".

While Android is based on open-source software, which in its purest form is distributed freely without the need to buy a licence, Oracle claims that Google has incorporated Java code into Android.

Google's operating system is sold on handsets from manufacturers including Motorola and Sony Ericsson. Sales of Android have been boosted by strong demand for smartphones globally.

Eric Schmidt, Google's chief executive, said last week that 200,000 smartphones and devices that use Android are sold every day. The case filed is Oracle of America Inc vs Google at a district court in northern California.

However, Google yesterday said: "We have not been served [legal documents] so we cannot comment until we have had a chance to review the complaint."