The Lusa A2 is a Portuguese blowback sub-machinegun, chambered for the usual 9mm caliber. The fire selector gives semi-auto, burst and full-auto at 900 rpm. It takes accessories such as lasers and suppressors. Unless I'm mistaken, it was invented in 1992, to replace the old FBP (M/948) model. The resemblance with the MP5 seems to be merely external, because of the blowback system. I wouldn't really know - I'm just a civilian. I know a bit about the FBP and the Uzi, which are both used by our armed forces. But I've only seen the A2 on the net and in Jane's Guns Recognition Guide book.
Photo and information from: LJ-38M & Pierangelo Tendas