BEIJING (TIP) : China said on May 21 it is entitled to keep watch over airspace and seas surrounding artificial islands it created in the disputed waters of the South China Sea, following an exchange in which its navy warned off a US surveillance plane. The United States said its aerial patrolling was in accordance with international law and “no one in their right mind” would try to stop it.

Neither side says it wants confrontation with the other, but as China seeks to assert its expansive claims to the South China Sea, the US is pushing back and trying to demonstrate that China’s massive land reclamation does not give it territorial rights.

A news crew from CNN reported it witnessed an incident Wednesday in which a Chinese navy dispatcher demanded eight times that a US Navy P8-A Poseidon surveillance aircraft leave the area as it flew over Fiery Cross Reef, where China has conducted extensive reclamation work. It said the US crew responded that they were flying through international airspace, to which the Chinese dispatcher answered: “This is the Chinese navy … You go!”

The Center for Strategic and International Studies think tank posted more video Thursday of the aerial patrol above the Spratly island chain which it said had been released by the US Navy.

Speaking at a regular daily briefing, Chinese Foreign Ministry spokesman Hong Lei reiterated Beijing’s insistence on its indisputable sovereignty over the islands it has created by piling sand on top of atolls and reefs.

While saying he had no information about the reported exchange, Hong said China was “entitled to the surveillance over related airspace and sea areas so as to maintain national security and avoid any maritime accidents. “We hope relevant countries respect China’s sovereignty over the South China Sea, abandon actions that may intensify controversies and play a constructive role for regional peace and stability,” Hong told reporters.

In Washington, Daniel Russel, the top U.S. diplomat for East Asia, said the flight of a US reconnaissance plane in international airspace over the South China Sea was a regular and appropriate occurrence.