That would be as close to a declaration of war as you can get without firing a bullet.
The immediate and obvious response would be for the foreign branches of those companies to be declared "of national interest", nationalized and forced to keep operating.
I'd imagine the government would be in talks with the highest ranking local Amazon employees long before, but I can't imagine a country trusting the hardware or wanting to manage the jank.
AWS China is a completely separate partition under separate Chinese management, with no dependencies on us-east-1. It also greatly lags in feature deployments as a result.
The immediate and obvious response would be for the foreign branches of those companies to be declared "of national interest", nationalized and forced to keep operating.