Directors of Apple and Google are being investigated by the US Federal Trade Commission (FTC) for potential violation of antitrust laws.

Google chief executive Eric Schmidt and former Genentech CEO Arthur Levinson both sit on the boards of the two companies. However, US law states that an individual can't sit on two boards if its decreases competition between the companies.

Both Google and Apple are rivals in the smartphone market, where Apple's iPhone goes head-to-head with handsets that use Google's Android platform, such as the T-Mobile G1.

The FTC has notified the individuals of its inquiry. Both Google and Apple refused to comment on the matter.