A US judge has ruled that Google acted illegally to maintain a monopoly on online searches and related advertising.

Google was sued by the US Department of Justice for its control of about 90% of the online search market.

In the decision, District Judge Amit Mehta noted that Google paid billions to ensure it is the default search engine on smartphones and browsers.

BBC News says the decision could reshape how technology giants do business in the future.

The company’s lawyers argued that users are attracted to their search engine because they find it useful, and that Google is investing to make it better for consumers.

Google is yet to formally respond to the ruling.