(Reuters) -China has flexed its muscles this month by sending an unusually large number of naval and coast guard vessels through a swathe of East Asian waters, according to security documents and officials, in moves that have unnerved regional capitals. Since early May, China deployed fleets larger than usual, including navy, coast guard and other ships near Taiwan, the southern Japanese islands and the East and South China Seas, according to three regional security officials and documents of regional military activities reviewed by Reuters. On May 21 and May 27, for instance, China deployed nearly 60 and more than 70 ships, respectively, around three-quarters of them naval, the documents show.