TOKYO/WASHINGTON – Japan and Southeast Asian countries called for freedom of the air and sea on Saturday, as China's military assertiveness raises regional tensions and after US and Chinese warships narrowly avoided collision in the disputed South China Sea. China's recent announcement of an air defense zone covering disputed islands in the East China Sea and its territorial claims in the South China Sea have raised concerns that a minor incident in the disputed seas could quickly escalate. The near-miss between a US guided missile cruiser, USS Cowpens, and a Chinese warship operating near China's only aircraft carrier, the Liaoning, last week was the most significant US-China maritime incident in the South China Sea since 2009, said security expert Carl Thayer at the Australian Defense Force Academy. “It is a gravely disturbing development,” said Ian Storey, a regional security analyst at Singapore's Institute of South East Asian Studies. “If China continues to challenge the presence of foreign naval ships in the South China Sea, it is only a question of time before a serious and potentially deadly incident occurs.” — Reuters