A U.S. Navy P-8A Poseidon reconnaissance plane, which was carrying a CNN news team on board Friday, flew past a series of artificial islands known as the Spratly Chain in the South China Sea. The plane reportedly received at least six separate warnings from the Chinese military to leave the area.

“U.S. military aircraft, papa 8 alpha, this is Chinese military. China has sovereignty over Nansha islands including the reef and its adjacent waters. Leave immediately and keep out so as to avoid any misunderstanding,” an unidentified voice said, according to recordings provided by CNN.

“I am conducting lawful military activity beyond the national airspace of any coastal state and exercising these rights as guaranteed by international law,” the U.S. Naval pilot operating the aircraft said. “I am operating with due regard to the rights of all states.”

China has claimed complete sovereignty over many parts of the South China Sea, of which Vietnam, the Philippines, Taiwan, Indonesia, Malaysia, and Brunei all claim overlapping portions.

The Chinese government says many parts of the South China Sea and the Nansha Islands “have been inherent Chinese territory since ancient times.”

Beijing’s “nine-dash line” reportedly extends over 1,000 kilometers, which the United Nations estimates accounts for one-third of the fleets that pass through for shipping purposes.

In June, the United States reportedly flew two B-52 bombers near the contested Spratly Islands in the South China Sea following several similar displays to respond to Chinese militarization of the region.

This week, Assistant Secretary of Defense for Asian and Pacific Security Affairs Randall Schriver said the United States Navy will continue to challenge Chinese claims over the South China Sea at the American Enterprise Institute. He added that the United States will continue “freedom of navigation” and said other U.S. allies could also join in on “presence activities.”

“I think what you’ll see is certainly a continuation of freedom of navigation,” Schriver said. “I think you’ll see perhaps more countries joining in presence activities — which if not a 12-nautical mile challenge presence in the South China Sea — is important because China claims the whole thing through the 9-dash line.”

Adelle Nazarian is a politics and national security reporter for Breitbart News. Follow her on Facebook and Twitter.