The Pentagon is drafting a new nuclear weapons strategy to prepare for a potential conflict with China or Russia, marking a significant shift in US military tactics.

The strategy, overseen by Elbridge Colby, the Pentagon’s policy chief, would place greater emphasis on shorter-range tactical nuclear weapons in the event of a regional war, rather than relying on long-range strategic missiles.

Mr Colby is expected to discuss the plans on Wednesday during a private military event in Nebraska while visiting the US Strategic Command, which oversees nuclear forces, NBC reported.

According to sources familiar with the plans, the strategy is designed to address scenarios in which US allies come under attack from Russia or China in a regional conflict.

A senior US defence department official told NBC: “Our view is that we need credible nuclear options.”

The strategy would not restrict Donald Trump’s choices but instead “expand the president’s option space by providing him with realistic and credible options and therefore strengthen deterrence”, the official said.

Mr Colby has long argued in favour of tactical nuclear weapons, which are smaller, shorter-range warheads designed for battlefield use or against specific military targets rather than entire cities.

He has also argued that the US existing nuclear doctrine lacks credibility because it relies heavily on the threat of launching long-range strategic weapons capable of destroying an adversary’s entire nuclear force.

The senior defence department official added: “If you actually want extended deterrence to be credible, you have to provide the nation’s political leadership with nuclear capabilities that common sense indicates you could actually use.

“Otherwise you’re reducing our leadership’s options to extreme choices that the adversary won’t find credible – and that is not going to fare well for deterrence.”

Read More: Pentagon draws up new nuclear weapons strategy for war with Russia and China