A bullet and blast resistance door leaf is comprised of inner and outer sheets connected by a profile section forming an end face of said leaf. The profile section includes an outer step and an inner step, the outer step extending laterally outwardly beyond the inner step. Outer and inner plates are connected to the outer and inner steps respectively, dividing the interior of the leaf into inner, outer and central chambers. A lock mechanism is mounted in the central chamber and projects through the profile, the lock mechanism being shielded by the outer plate. The inner and outer chambers may include insulation, and the outer chamber may include a sensor for activating an alarm.