9M113 Konkurs, a Russian anti-tank missile with the NATO reporting name "AT-5 Spandrel".
Apart from the mortar the vehicle is equipped with a 9M113 Konkurs (AT-5 Spandrel) ATGM, a 12.7 mm NSVT heavy machine gun, RPG-75 anti-tank grenade launchers, F1 hand grenades and Model 58 7.62 mm submachineguns.
In the spandrels around the dome are portrayals of the four Evangelists and four Fathers of the Church, painted by the Viennese artist J.G. Schmidt.