The speaker of Guam's legislative assembly is calling on the United States to brief the territory on the scope and nature of the planned military build-up.
Senator Judith Won Pat says Guam's government hasn't been consulted on a new plan to disperse thousands of marines stationed in Japan to other parts of the Pacific but she understands there's to be a decrease in the number transferred to Guam.
Agreement last year to relocate 8,000 Okinawa marines and their dependents to Guam as soon as possible after 2014 was part of a broader 2006 accord to reorganise American troops in Japan.
Ms Won Pat says it's time the US brought Guam into the loop.
"We are at their mercy, there's nothing we really can do other than to continue to bring up our concerns. At least they're now relooking at the firing range. We haven't heard anything yet about the upper harbour but the size is also what's important here that we need to know."
Judith Won Pat says Guam will benefit more if marines with families are transferred there.