Two-proton relative momentum distributions from the break-up channels Al-23 -> p+p+Na-21 and Mg-22 -> p+p+Ne-20 at an energy of 60-70 A MeV have been measured together with two-proton opening angles at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. The results demonstrate the existence of diproton emission component from single-step He-2 for highly excited Al-23 and Mg-22.