Sony Corp unveiled on Tuesday a smaller, lighter PlayStation handled game device called the PSP Go, in a race to catch rival Nintendo in an intensely competitive mobile games arena.

Hours before, Nintendo said it sold more than 15 million units of its blockbuster “Wii Fit” fitness game, and plans an update — the Wii Fit Plus — later this year.

Sales of the Wii have dwarfed those of more technically souped-up and pricier rival consoles from Microsoft Corp and Sony Corp, by broadening its audience beyond hard-core video gamers.

On the second day of E3, the largest U.S. video games conference, Sony and Nintendo vied for the spotlight, a day after rival console-maker Microsoft charmed audiences with its “Natal”: groundbreaking technology utilizing full-body motion-capture for gamers.

It was the first full day of the show, which is expected to draw some 40,000 game enthusiasts.

Many cheered and whooped at the press event at mere glimpses of new versions of popular games like “God of War” and “Super Mario Bros.,” or at the mention of secretive ones like “Agent,” which is being developed for the PS3 by the creators of “Grand Theft Auto.”