U.S. May Boost Military Presence in Northern Australia.

Australia's defense minister, David Johnston, will discuss the plan this week as part of broader talks including proposals for a larger ballistic-missile defense shield for U.S. allies in Asia.

"The interest here is for tactical aircraft, for closer cooperation between the Australian and U.S. air forces," said a local defense official familiar with Mr. Kerry's agenda.

The U.S. has around 1,150 marines and other military personnel that it rotates annually through Darwin. It has said it plans to more than double that number to create a 2,500-strong air and ground force in the northern city.

U.S. defense strategists value the relatively safer distance of Australian military bases from a potential Chinese missile strike than existing facilities in places such as Japan, South Korea and Guam, as well as access to large training and weapons ranges in remote areas.

For its part, Australia sees a growing U.S. military presence as crucial support to its own relatively small military given the regional instability in the East China Sea and South China Sea.

Senior American and Australian military officials are arriving in Darwin this week to observe one of Asia's biggest air combat exercises, involving seven nations. The biennial "Pitch Black" exercise brings together fighters from the U.S., Singapore, France, Thailand, the United Arab Emirates, New Zealand and host Australia.

The green light for a bigger U.S. military presence in Australia was obtained in June with an agreement between President Barack Obama and Australia's leader Tony Abbott that covers details such as the costs of building extra barracks and facilities in Darwin.

The deal, to be formally signed in Sydney this week, also places a legal framework around the U.S. military presence.