Recent images obtained by Radio Free Asia from the Earth imaging company Planet Labs show significant developments at the project that began just two years ago.

Compared to December last year, the base now has “several sets of sizable buildings including, possibly, administrative offices and barracks” at the center, according to Tom Shugart, Adjunct Senior Fellow with the Defense Program at the Center for a New American Security, who first spotted the developments.

In only six months, an area of reclaimed land in the southern part of the base has tripled in size.

However, the most striking new feature is a “deep draft pier” connecting to the central area of the base.

Back in February, analysts thought the pier was a temporary one to ferry in construction materials and equipment, but it has now turned out to be a permanent naval pier that could provide access to full-size warships of the People’s Liberation Army (PLA) Navy.

But despite the Pentagon's concerns, Ream naval base suffers from serious limitations to its military viability, as shallow waters prevent large military vessels from docking. The site also lacks defense against air strikes.

"It's not the world's most desirable place for a naval base," said Peter Layton, visiting fellow at the Griffith Asia Institute in Australia. "It doesn't seem from a warfighting viewpoint that anyone would be too concerned."