Minister at Singapore defence summit also reveals Australia to buy only secondhand Aukus submarines from US Follow our Australia news live blog for latest updates Get our breaking news email, free app or daily news podcast The defence minister, Richard Marles, has said the “seabed is a battlefield” in a combative speech urging Beijing to be more transparent about its maritime operations, and taking aim at weak international controls over so-called “shadow-fleet” vessels. The warning came as t