The Pentagon foresees a “more limited” role in deterring North Korea, with South Korea taking primary responsibility for the task, a Pentagon policy document released on Friday said, in a move likely to raise concern in Seoul.

South Korea hosts about 28,500 US troops in combined defence against North Korea’s military threat and Seoul has raised its defence budget by 7.5% for this year.

“South Korea is capable of taking primary responsibility for deterring North Korea with critical but more limited US support,” said the National Defense Strategy, a document that guides the Pentagon’s policies.

“This shift in the balance of responsibility is consistent with America’s interest in updating US force posture on the Korean Peninsula,” the document added. In recent years, some US officials have signalled a desire to make US forces in South Korea more flexible to operate outside the Korean peninsula in response to a broader range of threats, such as defending Taiwan and checking China’s growing military reach.

South Korea has resisted the idea of shifting the role of US troops, but has worked to grow its defence capabilities in the past 20 years, to take on a wartime command of the combined US-South Korean forces. South Korea has 450,000 troops.

The wide-ranging document, which each new administration publishes, said the Pentagon’s priority was defending the homeland. In the Indo-Pacific region, the document said, the Pentagon was focused on ensuring China could not dominate the US or its allies.

“This does not require regime change or some other existential struggle. Rather, a decent peace, on terms favourable to Americans but that China can also accept and live under, is possible,” the document said, without mentioning Taiwan by name in the roughly 25-page document.

China claims democratically governed Taiwan as its own territory and has not ruled out the use of force to take control of the island. Taiwan rejects Beijing’s sovereignty claims and says only the people of Taiwan can decide their future.