A Filipino diplomat is warning that any Chinese move to turn a disputed shoal, where the U.S. Navy has detected a suspected Chinese survey ship, into an island will escalate the disputes in the South China Sea and asked Washington to help convince Beijing not to take that "very provocative" step.

Philippine Ambassador to Washington Jose Cuisia Jr. told a news conference in Manila on Tuesday that the U.S. Navy spotted the suspected survey ship in the Scarborough Shoal a few weeks ago and expressed concerns about its presence in the disputed area.

Cuisia says he was involved in a U.S.-brokered deal for China and the Philippines to withdraw their ships simultaneously from Scarborough to avoid a potential clash during a 2012 standoff but Beijing reneged on that deal.