The file photo shows a Russian intercontinental ballistic missile launcher. (AFP)

The United States must be prepared for potential simultaneous wars with China and Russia, a new bipartisan Congressional report says, warning that the US is currently not ready for facing two nuclear powers for the first time.

A new report by a Congressionally mandated commission - titled America’s Strategic Posture - released on Thursday, warned that the US must either expand its conventional forces or restructure its nuclear arsenal to tackle the existential challenge posed by the alleged nuclear threat from China and existing risk from Russia.

Released by the Congressional Commission on the Strategic Posture of the United States, the 160-page assessment was the result of a year-long effort by a group of leading bipartisan nuclear experts.

It is an existential challenge for which the United States is ill-prepared, unless its leaders make decisions now, the report says, focusing heavily on a worst-case scenario of coordinated Russian and Chinese aggression.

The report comes amid tensions between Washington and Beijing over Taiwan plus other issues, and deteriorating frictions between the White House and the Kremlin over Russia’s war in Ukraine.

The new global environment is fundamentally different than anything experienced in the past, even in the darkest days of the Cold War. The US is on the cusp of having not one, but two nuclear peer adversaries, each with ambitions to change the international status quo, by force, if necessary, it cautioned.

The new assessment would overturn current US national security strategy, calling for winning one conflict while deterring another. It also calls for huge defense spending increases with uncertain Congressional support.

While it requires significant investment to maintain a strategic posture sufficient to prevent war with a major power, it will be far more expensive, in lives and resources, to fight such a war, the report said.

The panel warned that the US is currently without a comprehensive strategy to tackle two simultaneous nuclear wars with its two big rivals, calling on Washington to invest more in missile defense, including systems that could deter and defeat coercive attacks by Russia and China.

US defense strategy to address the two-nuclear-peer threat requires a US nuclear force that is either larger in size, different in composition, or both, it said, stressing that Washington lacks a comprehensive strategy to address the looming two-nuclear-peer threat environment.

Following the release of the report on Thursday, Roger Wicker, a top Republican on the US Senate Committee on Armed Services expressed his worries over the US’s current military might in case such wars break out.

It is apparent from the report that there is much more that we should be doing to ensure our military, and particularly our nuclear forces, are capable of deterring two near-peer nuclear adversaries at the same time, he said.