Pompey have signed former French under-21 international Yassin Moutaouakil.
The 26-year-old full-back trained with the Blues today.
Shaun Cooper, Adam Reed and Sam Sodje have also agreed one-month deals with the club.
Moutaouakil had been with Blue Square Bet South side Hayes & Yeading before being invited to train with Pompey.
The defender has played for Ligue Two side Châteauroux, Charlton and Motherwell during his career.
He also had a trial with Pompey during the 2009 pre-season but then manager Paul Hart turned down the chance to sign him.