FILE PHOTO  -  Chinese dredging vessels are purportedly seen in the waters around Mischief Reef in the disputed Spratly Islands in the South China Sea in this still image from video taken by a P-8A Poseidon surveillance aircraft provided by the United States Navy May 21, 2015. U.S. Navy/Handout via Reuters/File Photo   ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. EDITORIAL USE ONLY. THIS PICTURE WAS PROCESSED BY REUTERS TO ENHANCE QUALITY. AN UNPROCESSED VERSION IS AVAILABLE IN OUR ARCHIVE.
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