artillery barrage killed four people in the south. greg palkot is live from the capitol of seoul. greg, tense times as you've laid out for us this week. what's the latest? >> reporter: tense times, martha, but as you noted, two tracks seem to be developing in the past couple of days to deal with north korea, both the military and diplomatic track. first on the military side, the joint u.s., south korea naval exercises continue. we're told the exercises today involve interdiction on the high seas of weapons of mass destruction on ships, clearly aimed at possible coming from north korea, also on yeonpyeong island, the police hit by north korean artillery one week ago, security being bolstered and on the diplomatic side, word today that the foreign minister from south korea and japano japan will come to washington, d.c. next week to meet with secretary of state clinton and on the other side up in bay skwreubg, north korean envoy, a top envoy from