A US Navy commander has spoken for the first time about a photograph of Chinese aircraft carrier the Liaoning taken from its guided missile destroyer USS Mustin during their close encounter in the disputed South China Sea last year. Vice-Admiral Roy Kitchener, commander of US Naval Surface Forces, said the USS Mustin shadowed the Liaoning last April and was able to take photographs and observe that the Chinese carrier was subject to “operating restrictions”. US crew members “realised that at some point all the Chinese escorts sort of backed off” because “there’s some operating restrictions that they had around the carrier”, he told the annual Surface Navy Association conference on Tuesday, according to US news website Business Insider. “Mustin didn’t have those [restrictions],” he said. “They proceeded on in, found a good station, and sat alongside taking pictures and doing other things for quite a bit of time.” Kitchener said the episode had irritated China, which told the US State Department the Mustin was “no longer welcome in the South China Sea”, but he said it “was a good story in the end” and Mustin’s crew had commemorated the encounter on a uniform patch. “To me, that shows the boldness and what sailors are trained to do,” Kitchener said. The Liaoning may have been busy with a complicated drill, allowing US officers to take photos, said Lu Li-shih, a former instructor at Taiwan’s Naval Academy in Kaohsiung. One photo showed the USS Mustin’s captain and deputy commander sitting side by side to watch the Liaoning, which was a few kilometres away. The photo was distributed around the world and widely interpreted as a message to the People’s Liberation Army (PLA). “It’s very common for warships to sail so close for parallel monitoring in unexpected encounters at high sea,” Lu said. “But it’s rare for the captain and his deputy to sit together, showing that the Liaoning gave the Mustin quite a lot of time to take the picture because of its operating restrictions.” South China Sea: the dispute that could start a military conflict Former Chinese military instructor Song Zhongping said the PLA followed planned voyage routines whereas the American crews’ operating guidelines were more flexible. The published photo was last year chosen for a Chinese navy picture gallery to mark its 72nd anniversary. Beijing-based military expert Zhou Chenming suggested that it showed the Americans’ concern about a rising China. Collin Koh, a research fellow at the S. Rajaratnam School of International Studies in Singapore, said the encounter indicated that both the Chinese and American sides had abided by the Code for Unplanned Encounters at Sea. “Unless necessary … no sane naval leadership wishes to put their own crews in harm’s way while executing bravado manoeuvres in peacetime that achieve little to no political purpose,” he said. “Under normal peacetime conditions, safe and professional interactions would be an operational priority, aside from fulfilling their mandated missions.”