The Pentagon is preparing US military bases to operate independently for at least 90 days in the event of a major conflict that could disrupt power grids, supply chains and critical infrastructure across the US.

The initiative is part of a program known as FORTRESS, according to Fox News.

Under the program, military bases would be equipped with independent power sources and sufficient reserves of fuel, water, ammunition and other essential supplies to sustain operations during prolonged disruptions. The plan also envisages the possibility of converting civilian industrial facilities to military production to meet wartime demands.

Pentagon spokesman Sean Parnell said that the next conflict would likely be fought on multiple fronts and that global supply chains would break down as a result.

The preparations are intended to strengthen the military's ability to maintain operations if a large-scale conflict severely disrupts essential services and supply networks.

However, the Fox News report describes broader preparations for a potential major war. It does not indicate that the Pentagon plans to conduct continuous military operations against Iran for 90 days.