Sony Corp unveiled a new handheld gaming device on Thursday as it battles with Nintendo Co Ltd's best-selling DS and tries to fend off rising competition from smartphones and tablets.

Sony said it has codenamed the new device NGP for Next Generation Portable.

The announcement came the same day Nintendo is expected to report a slide in quarterly profits. Sales of Nintendo's aging DS handheld are tumbling ahead of the launch of its glasses-free 3D-capable version next month.

(Reporting by Isabel Reynolds; Editing by Anshuman Daga)