Guam Naval Base (Picture: PA images).
Donald Trump is raising a proportion of the money for his border wall with Mexico by deferring funds for military projects in Guam.
About 7% of the funds for the 3.6 billion dollar (£2.9 billion) wall are being moved from eight projects in the US territory.
The island, with a population of 160,000, is a strategic hub for US forces in the Pacific.
The administration says it is merely delaying the spending, not cancelling it.
Democrats in Washington, outraged over the US President's use of an emergency order for the wall, say they will not approve money to revive the projects.
The Senate on Wednesday passed a measure blocking Mr Trump from raiding the military construction budget for the wall.
The Democratic-controlled House passed the bill on Friday, but Mr Trump is expected to veto it as he did with an identical measure in March.
Guam holds a naval base with fast-attack submarines, and an Air Force with bombers rotating from the mainland.
There are plans to move 5,000 marines there from Okinawa, Japan, around 2025.
However, the deferred funding may disrupt that, as well as plans to modernise munitions storage for the Air Force.
Representative Ed Case is a Democrat from Hawaii who sits on the House appropriations subcommittee for military construction.
He said the developments are concerning, given the island is key to the nation's defence posture in the Pacific.
"That is a very difficult situation because these are priority projects.
"However, if we simply said yes to this president on that basis, which he is very much hoping that we will do, then we have essentially said to him and any future president that Congress' role as the responsible branch of government for appropriations no longer counts."