Cambodia has razed a US-funded defence facility on its southern coast, the deputy prime minister confirmed Sunday, the latest move in the ongoing controversial expansion of a strategically crucial naval base being developed with Chinese aid.

The Wall Street Journal reported last year on a secret draft deal allowing China to dock warships at the Ream naval base near the kingdom’s coastal city of Sihanoukville.

But Cambodia — awash in recent years with Chinese investments — has strenuously denied the report, although strongman premier Hun Sen has said aid from Beijing will fund the naval base’s development.

With increasingly sophisticated Russian submarines prowling the Atlantic, the U.S. Navy is working harder to keep track of what’s happening off the U.S. coast.

The Navy’s focus on anti-submarine warfare waned during the Middle East wars, but attention is shifting, underscored by Exercise Black Widow 2020 in the North Atlantic between September 12 and 18.

The deterioration of Russia’s navy in the decade after the Cold War “allowed a lot of folks to think that the homeland is a sanctuary from Russian forces,” Vice Adm. Daryl L. Caudle, commander of Naval Submarine Forces, told reporters on September 16.

“But it’s pretty well known now that our homeland is no longer a sanctuary, so we have to be prepared here to conduct high-end combat operations in local waters,” Caudle added.