Much of its defense work was highly classified and remained strictly 'off-limits' to the public sector.

These proceedings are strictly classified, and if you mention them to anyone, I will personally see that you rue this day.

However, that information is strictly classified.

Their existence remained strictly classified throughout the reign of Nicholas I.

Special protection areas - strictly protected sites classified for rare and vulnerable birds.

Furthermore, the aliens were strictly classified according to their class of permit.

Nowadays, a new star may be classified as main sequence strictly by its color.

Everything between them was strictly classified.

None of these could be classified strictly as proletarians, even by the loose and ideologically biased definitions of the early Soviet period.

"All details of a technological nature are strictly classified."