TOKYO (BLOOMBERG) - The United States and Japan reached an agreement on costs Tokyo will bear to continue hosting tens of thousands of American troops, a bulwark against China and a key part of the Pentagon's Indo-Pacific strategy.

The accord, which covers the 2022-2026 period, will see Japan spending an average of 211 billion yen (S$2.46 billion) to host about 50,000 American troops and their families, a presence that has at times been contentious. That's roughly in line with expenses in recent years.

"Bilateral defence cooperation under Host Nation Support will contribute to the enhancement of readiness and resiliency of the Alliance, including by improving the interoperability of US forces and the Self-Defence Forces of Japan," according to a statement on Tuesday (Dec 21) from Japan's Ministry of Foreign Affairs.

Japan and the US reached a five-year deal in 2016 in which Tokyo bears costs for local staff, utilities and training relocation.

In 2019, Japan was set to pay about 197 billion yen, although the US does not publish costs of maintaining its bases in the country.

Some military experts have said it's probably cheaper for the US to keep its troops in Japan than to bring them home.

Japan's statement was confirmed by a State Department official on customary condition of anonymity.

A State Department spokesman said: "This demonstrates the strength of the US-Japan Alliance, which is the cornerstone of peace and security in the Indo-Pacific and beyond."

During the Trump administration, the US sought to increase payments for hosting American forces as much as five-fold.

While then-President Donald Trump largely focused his demands on South Korea, those negotiations were seen as potentially impacting any future US deal with Japan.

Under a 1951 security treaty, the US is obligated to defend Japan, which under its US-drafted constitution, renounced the right to wage war after World War II.