Senior US commanders have highlighted the importance of land-based troops and equipment stationed in the Asia-Pacific in any conflict with China, countering assumptions that such a war would be fought mainly at sea and in the air.

General Ron Clark, commander of US Army Pacific, said the “tyranny of distance” made it difficult to rely on air and naval forces during a panel discussion at the Association of the United States Army’s annual meeting this week.

The comments reflect mounting concerns among US commanders that China’s increasingly sophisticated air and naval forces could stop American forces operating freely in the region, leaving them in greater need of land-based support.

Clark commands more than 107,000 soldiers deployed in US Pacific territories and in allies such as South Korea and Japan, with rotational deployments in the Philippines.

He said the command covered “17 time zones, 52 per cent of the Earth’s surface, 60 per cent of the Earth’s population, four billion people, 25 per cent of the world’s land mass”.

Deterrence had been “successful” because of the US Army’s combat-ready posture, “set forward” at scale in the first and second island chains, he added.

Clark said the army now had the “true capability to operate across all domains” within the first and second island chains – strategically vital groups of islands that stand between China and the open waters of the Pacific – adding that this had “changed the outcome” in a series of war games.

He said that without the army “holding terrain and providing the sustainment”, the air force and navy could not employ their “exquisite capabilities”.

“Our ability to provide integrated air missile defence across the entirety of the region is an army capability that is leveraged by the joint force,” he added.

Without naming China directly, Clark said “our adversary” had devised a strategy tied to “anti-access area denial” – a term American planners use for the People’s Liberation Army’s plans to keep adversaries such as the US out of strategically vital areas.

Countering it required the US Army to provide assistance for air and sea “operations that can pulse into an access-denied environment”, he added.

China has been steadily modernising its armed forces and has set a series of goals to be reached by politically symbolic dates such as 2027, 2035 and 2049.

US intelligence and military officials have frequently cited these as a possible timeline for the PLA’s readiness to take Taiwan by force.

Beijing views Taiwan as part of China and has never renounced the use of force to bring it under its control. Most countries, including the US, do not recognise the self-ruled island as independent, but Washington opposes any use of force and is legally committed to providing Taipei with arms.

China’s military reforms have focused on air and sea power, and in recent years it has unveiled a series of advanced weapons such as the Fujian aircraft carrier, the J-35 fifth-generation fighter jet and various unmanned and autonomous systems.

Clark’s remarks reflect the US Army’s shift towards multi-domain operations, integrating cyber, space and electronic warfare.

In June, the US Army set up the Multi-Domain Command-Pacific at Joint Base Lewis-McChord in Washington state to support joint and allied operations across the Indo-Pacific region.

Joshua Arostegui, chair of China studies and research director of the China Landpower Studies Centre at the US Army War College, said there had been a “broader structural shift” in America’s defence strategy.

“In an era where long-range precision fires and unmanned aerial systems are proliferating, the traditional model of massing large, static land forces is largely recognised as obsolete,” said Arostegui.

“Instead, the Army is adapting to serve as a foundational ‘inside force’, designed to selectively fracture adversary networks so the broader joint force can operate effectively.”Shaun McDougall, a lead analyst covering the US defence market at Forecast International, said drone and missile threats were becoming “more ubiquitous”.

“[Multi-domain task forces] are intended to serve as a deterrent to countries like China or to respond accordingly should a conflict arise,” said McDougall.

“The army has also been prioritising its own development of unmanned systems, long-range strike platforms and air and missile defence capabilities.”Liselotte Odgaard, a senior fellow at the Hudson Institute, said long-range missiles such as the Typhon and High Mobility Artillery Rocket Systems were one of the army’s “most significant contributions to deterrence against China”.

“By creating multiple axes of threat, they raise the costs and risks of any Chinese attempt to project power beyond the first island chain or conduct operations against Taiwan,” she said.

Meanwhile, Beijing’s latest five-year plan prioritised the transition towards “intelligentised” warfare, emphasising the importance of artificial intelligence, unmanned and autonomous systems, networked information infrastructure and emerging technologies.

Clark said the wars in Iran and Ukraine offered lessons on how land-based forces could have an impact on aerial and naval warfare, particularly through long-range precision strikes and integrated air and missile defence.

“In those two theatres [Iran and Ukraine], it’s not a near-peer adversary that we would be working against. Whereas in our theatre, it absolutely is,” said Clark.

He said this raised the question of how the Army would tackle drones and ballistic missiles in an archipelagic environment.

Speaking alongside Clark, General Xavier Brunson, commander of United States Forces Korea, said alliances offered the US “distributed locations” that offered a “position of advantage”, helping to protect critical assets from sensors and drones.

He added that US adversaries were trying to imitate the network of alliances that the US had built, saying: “So if you look at Russia and [North Korea] and China, you see them continuing to collude … Well, they’ve learned that from us.”Odgaard said air defence and counter-drone capabilities had “significantly” increased the army’s importance given the possible threat from missiles and drones in the Indo-Pacific.

Arostegui said integrated air and missile defence was “perhaps the US Army’s most essential strategic contribution” in the region.

“Given the rapid advancement and proliferation of ballistic, cruise and hypersonic technologies, these fixed locations face acute vulnerabilities that only layered, ground-based defence systems … can mitigate,” he said.

“Consequently, robust air and missile defence transforms the Army into a foundational prerequisite for any sustained military operation or crisis response in the region.”