Countering China’s rapidly expanding military and an increasingly aggressive Russia are now the US military’s top national security priorities.

US defence secretary James Mattis said competition with those adversaries has threatened America’s military advantage around the world and has overtaken the threat of terrorism.

Laying out a broad new strategy for the Defence Department, Mr Mattis warned that all aspects of the military’s competitive war fighting edge have eroded.

He said building a force that can deter war with established and emerging military powers in Moscow and Beijing, and US enemies such as North Korea and Iran will require increased investment to make the military more lethal, agile and ready to fight.

“We will continue to prosecute the campaign against terrorists that we are engaged in today, but great power competition — not terrorism — is now the primary focus of US national security,” he said in remarks at the Johns Hopkins School of Advanced International Studies.

Mr Mattis said the Islamic State group’s “physical caliphate” in Iraq and Syria had been defeated, but that IS, al Qaida and other extremists still pose threats across the globe.

He repeated his call for America to work closely with allies and partners — an approach that aligns more closely with previous administrations than US President Donald Trump’s “America First” ideas. That mantra was repeated in a national security strategy that Mr Trump’s administration released in December.

The US and its allies, Mr Mattis said, are stronger together. He recalled going to his first NATO meeting last year, carrying Mr Trump’s demand for nations to increase their defence spending and thinking about how to fit Mr Trump’s message into the broader framework of working with partners.

When he got to Brussels, Mr Mattis said he told the alliance: “Here’s the bottom line: Please do not ask me to go back and tell Americans — the American parents — that they need to care more about the safety and security and the freedom of your children than you’re willing to care for, than you’re willing to sacrifice for. We’re all going to have to put our shoulder to the wagon and move it up the hill.”

(AP Photo/Jacquelyn Martin)
(AP Photo/Jacquelyn Martin)

The most dominant theme in his strategy is for the US to regain its competitive edge with China and Russia, according to an 11-page, unclassified version released by the Pentagon.

That shift reflects persistent US worries about China’s military buildup in the South China Sea, its moves to expand its political and economic influence, and what has been described as Beijing’s systematic campaign of cyber attacks and data theft from government agencies and private US corporations.

The shift also underscores broad American concerns about Russia, given Moscow’s takeover of Ukrainian territory, involvement in Syria’s war and alleged meddling in the 2016 US presidential election.

“We’ve been doing a lot of things in the last 25 years, and we’ve been focused on really other problems and this strategy really represents a fundamental shift to say, look, we have to get back, in a sense, to basics of the potential for war,” said Elbridge Colby, the deputy assistant defence secretary for strategy. “This strategy says the focus will be on prioritising preparedness for war and particularly major power war.”