New Delhi, Oct. 27 -- The Pentagon is preparing major US military installations to operate independently for at least 90 days without outside support as it steps up preparations for a potential major war that could cripple power grids, disrupt global supply chains and threaten critical infrastructure on American soil, a report said.

The requirement is part of FORTRESS, a broader military initiative designed to ensure American forces can continue operating even if the civilian infrastructure they depend on is disrupted, according to documents reviewed by Fox News Digital.

"We don't want to rely on standard civilian municipal infrastructure to run our national defense. We just simply can't. It's an intolerable risk," the news outlet quote...