Microsoft and Sony are launching a video-game offensive against Nintendo this week, as the clear leader in console sales shows its first signs of flagging.

Industry executives and analysts gathering in Los Angeles for the main show of the year – the Electronic Entertainment Expo (E3) – expect Microsoft to announce a new motion-sensing game controller today, with more sophisticated capabilities than the one that has driven the success of Nintendo's Wii.

Then tomorrow, Sony plans to show off a new version of its PlayStation Portable – the PSP Go – that does not require an optical disc drive. It is designed to take on the latest version of Nintendo's DS handheld console, as well as tackle emerging competition from Apple's growing games platform, in the shape of the iPhone and iPod Touch.