Japan and South Korea agreed Sunday to expand joint maritime search-and-rescue exercises and strengthen communication as the two U.S. allies continue to deepen defense cooperation amid their improving ties.Meeting in Seoul, Japanese Defense Minister Shinjiro Koizumi and his South Korean counterpart Ahn Gyu Back welcomed the resumption earlier this month of humanitarian search-and-rescue drills between the Japan Maritime Self-Defense Force and the South Korean Navy, the Japanese Defense Ministry said.The June 7 exercise was the first in about nine years. The two countries' ties have improved after years of strained relations over issues stemming from Japan's wartime past.The ministers agreed to expand the drills to improve coordination in responding to maritime emergencies and reaffirmed t…