The former commander of the US Army in Europe has warned it is "very likely" his country will be at war with China in 15 years.
Retired Lieutenant General Ben Hodges said European allies will have to do more to protect themselves in the face of a resurgent Russia, as the US will need to focus on defending its interests in the Pacific.
Lt Gen Hodges was speaking at the Warsaw Security Forum in Poland, a two-day gathering of military leaders and political experts from central Europe.
He said: "The United States needs a very strong European pillar.
"I think in 15 years - it's not inevitable - but it is a very strong likelihood that we will be at war with China.
"The United States does not have the capacity to do everything it has to do in Europe and in the Pacific to deal with the Chinese threat."
Lt Gen Hodges was US Army commander in Europe from 2014 until 2017.
He now is a strategic expert with the Center for European Policy Analysis, a Washington-based research institute.
Despite shifting geopolitical priorities, Lt Gen Hodges said the US commitment to NATO remains "unshakeable".
He added he is certain the Trump administration views Europe's security as a key US interest.
This comes despite President Donald Trump having sometimes questioned the Western military alliance's usefulness.
Lt Gen Hodges said: "You're going to see us continue to invest here in Europe, continue to train, to practice rotational forces, as well as permanently assign forces for the eventuality that in 10 or 15 years we're going to be having to fight in the Pacific."
He added that a recent near-miss between a US Navy destroyer and a Chinese warship in the disputed South China Sea was only one of the signs pointing to "an increasingly tense relationship and increasing competition in all the different domains."
The former commander added that another sign is China's "constant stealing of technology", and how the superpower is gaining control of infrastructure by funding projects in Europe and Africa.
He said that the country owns more than 10% of the ports in Europe.
The US and China are engaged in a trade war , with Mr Trump imposing $200bn worth of tariffs on Chinese goods in September.
China's foreign ministry announced a series of retaliatory tariffs on $60bn of US imports.