You can only build them on your own territories (that you have controlled since the beginning of your turn).
Building ICs…
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If at the beginning of my turn I build an IC and two tanks.
Can I place the IC in a given zone and then have the tanks built there or do they have to go to a preexisting location? -
You can not build units at industrial complexes you captured or built in the same turn. (page 20, 1st paragraph)
So, they have to go to a preexisting location.





