Japan and Australia have recently agreed to launch joint research on the future development of underwater drones, as the countries step up defense cooperation amid China's maritime assertiveness in the Indo-Pacific region.

It is the first specific project the U.S. allies will work on since they signed a deal last June to simplify procedures for joint technical studies on defense equipment, according to the two governments.

The project is intended to contribute to future interoperability of unmanned underwater vehicles between the two nations, the Defense Ministry said in a press release issued late last month upon the signing, referring to the capabilities that could potentially be used for detecting mines and other missions.

Simulations will be run on underwater communications by using each other's information on the marine environment, according to the ministry.

"Maintaining a technological edge in our rapidly changing strategic environment is vital," Australia's Chief Defense Scientist Tanya Monro was quoted as saying by the Australian Department of Defense in a separate press release.

The two countries will deliver science and technology outcomes that they "cannot achieve alone," and the project will build a "foundation for future joint research on robotic and collaborative autonomy," she added.

Bilateral defense ties have deepened in recent years, with Japanese government sources saying in January that the two countries have been discussing potential cooperation in case of simultaneous military contingencies in their respective nearby areas.

Australia, for its part, has been teaming up with the United States and Britain under the AUKUS partnership to beef up its submarine capabilities and develop advanced technologies such as autonomous underwater vehicles, saying such drones could be "a significant force multiplier" for their maritime forces.

China's assertiveness has been a source of tension in the region. Canberra expressed serious concern in November about the use of sonar by a Chinese warship when Australian navy divers were operating in waters near Japan — an incident Beijing has denied.

Australian Deputy Prime Minister and Defense Minister Richard Marles said in a recent interview in Canberra that he hopes to see Japan collaborate with AUKUS on defense technology development in the future.