The US State Department has approved the possible sale of 17 Bell Boeing V-22B Block C Osprey tiltrotor aircraft to Japan.

The potential Foreign Military Sales deal is valued at $3 billion, says the US Defence Security Cooperation Agency in a statement.

The deal also comprises 40 Rolls-Royce AE1107C engines, sensors, missile warning receivers, counter measures systems, and other equipment and services. The key contractors will be Bell Helicopter and Boeing Rotorcraft Systems.

When Tokyo released its FY2015 defence budget in January, it provided funding for five V-22s that will form part of a new amphibious capability modelled on the US Marine Corps. News of the 17 aircraft acquisition had previously emerged in a Japanese budget document in November 2014.

“Japan is modernizing its transport fleet to better support its defense and special mission needs,” says the DSCA.

“The proposed sale of V-22B Block C Osprey aircraft will greatly enhance the Japan Ground Self-Defense Force’s humanitarian and disaster relief capabilities and support amphibious operations. This sale will promote burden sharing with our ally and interoperability with US forces. Japan will have no difficulty absorbing these aircraft into its armed forces.”

China’s increasing assertiveness about territorial claims in the East China and South China Seas has sparked concern among the countries on its periphery. Moreover, Tokyo and Beijing have overlapping territorial claims, which have raised concerns about the potential for war.