US Secretary of State Antony Blinken announced that the two nations were signing a five-year extension of the support package provided by Japan for the hosting of around 50,000 US troops on its soil.

The new agreement "will invest greater resources to deepen our military readiness and interoperability," Blinken said at the opening of four-way virtual talks between the allies' foreign and defence chiefs, held Friday Tokyo time.

"Our allies must not only strengthen the tools we have but also develop new ones," Blinken said Thursday in Washington.

Defense Secretary Lloyd Austin, appearing from isolation after a mild case of Covid-19, said the allies were "evolving our roles and missions to reflect Japan's growing ability to contribute to regional peace and stability."

Japan renounced its right to wage war after World War II and has since developed a close alliance with Washington, which is treaty-bound to defend the world's second-largest developed economy.

Tokyo pays the costs of the US forces in the country as well as utilities. A previous agreement was set to expire in March 2021 but was extended for a year amid a change of administration in Washington.

According to Japanese press reports, the new five-year package will amount to 211 billion yen ($1.8 billion) per fiscal year, an increase of about five percent.

The package comes amid growing tensions with China, which has stepped up incursions near Taiwan, a self-ruling democracy that enjoys close ties with Washington and Tokyo but which Beijing considers a province awaiting reunification.

"Beijing's provocative actions keep raising tensions across the Taiwan Strait and in the East and South China Sea," Blinken said.

He also described North Korea's missile programs as an "ongoing threat" after Pyongyang fired a suspected ballistic missile into the sea.

A joint statement issued after the talks took aim at "efforts by China to undermine the rules-based order," with specific reference to activity in the East and South China Seas.

The allies also expressed "serious and ongoing concerns" about rights violations in China's Xinjiang region and Hong Kong, and called for "peace and stability" in the Taiwan Strait.

Japan's Foreign Minister Yoshimasa Hayashi told reporters later that he again raised the issue of Covid clusters on US bases, which are believed to have spilled over into local communities in several areas.

Japan's government is expected to approve Friday new virus restrictions in three regions that host US bases, and Hayashi said he had urged "the US side to strengthen anti-infection measures including efforts like introducing limits on off-base outings".