The United States military has engaged in a form of "cognitive warfare" following the latest encounter between its warships and the Chinese navy.
Both countries have deployed aircraft carrier strike groups to the East and South China seas, led by the USS Theodore Roosevelt and the Liaoning, respectively.
On Sunday, the US released a photo that showed one of its guided-missile destroyers, the USS Mustin, shadowing the Liaoning group - a move that analysts said was designed to send a clear message to the Chinese.
The photo taken on Monday somewhere in the East China Sea showed the ship's captain, Commander Robert J Briggs, and his deputy Commander Richard D Slye watching the Liaoning, which was just a few thousand metres away.
"In the photo, Commander Briggs looks very relaxed with his feet up watching the Liaoning ship just a few thousand yards away, while his deputy is also sitting beside him, showing they take their PLA counterparts lightly," said Lu Li-shih, a former instructor at Taiwan's Naval Academy in Kaohsiung.
"This staged photograph is definitely 'cognitive warfare' to show the US doesn't regard the PLA as an immediate threat."
Zhou Chenming, a researcher with the Yuan Wang think tank, a Beijing-based military science and technology institute, said the photo indicated that the US warship kept a "very safe distance" while shadowing the Liaoning.
"Both sides understand that there is a big gap between the US and Chinese aircraft carrier strike groups," Zhou said.
Andrei Chang, the editor-in-chief of the Canada-based Kanwa Defence Review, said the photo was a "warning to the PLA" that the US was thoroughly informed about the Liaoning strike group.
The Beijing-based South China Sea Strategic Situation Probing Initiative said the US military had increased the deployment of aircraft and warships to the East and South China seas.
It also said the USS Mustin had been sent to waters near the mouth of the Yangtze River on April 3, and since last Sunday has been following the Liaoning group through the East and South China Seas.
The Liaoning aircraft carrier group also includes the Nanchang, one of China's most advanced Type 055 destroyers, two other destroyers, a frigate and a support ship.
The Japanese defence ministry is also reported to have sent the destroyer JS Suzutsuki and two patrol aircraft to monitor the strike group as it passed between Okinawa and Miyako Island on Sunday.
Meanwhile, US Defence Secretary Austin Lloyd had a phone conversation with his Philippine counterpart Delfin Lorenzana to reaffirm their shared commitment to their alliance after Chinese vessels massed at a disputed reef, according to the Pentagon.
China has described the presence of the 200 vessels near Whitsun Reef as "normal and legitimate" and said officials are maintaining close communications with the Philippines.
But the Philippines has described the vessels as a maritime militia and last week the broadcaster ABS-CBN claimed two Chinese vessels armed with missiles drove away the ship carrying its news crew near the island province of Palawan. The broadcaster said it was the first recorded instance of a military manoeuvre against a civilian boat.
Macau-based military observer Antony Wong Tong said the report indicated that the PLA had deployed Type 022 missile boats to Mischief Reef, one of the seven artificial islands Beijing has reclaimed in the disputed Spratly Islands, which are just 250km (155 miles) from Palawan.
"The massing of China's maritime militia vessels at Whitsun Reef implies that Beijing may attempt to resume its land reclamation project in the Spratly Islands because of the geostrategic location of Whitsun Reef, which is located between Fiery Cross Reef and Mischief Reef," Wong said.
"China realised Mischief is too far away from the mainland and too isolated in the Spratlys, but land expansion based around Whitsun Reef will solve the problem."
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