Not just chip fabs; also data centers. According to Eliezer S. Yudkowsky, if push comes to shove, we can also order airstrikes against the latter:

If intelligence says that a country outside the agreement is building a GPU cluster, be less scared of a shooting conflict between nations than of the moratorium being violated; be willing to destroy a rogue datacenter by airstrike.

https://time.com/6266923/ai-eliezer-yudkowsky-open-letter-no...