SEOUL, South Korea (AP) - North Korea's military says it artillery forces are at their highest-level combat posture in its latest threat to attack South Korea and the U.S. Seoul says it isn't seeing any suspicious North Korean military activity. Analysts say a direct North Korean attack is extremely unlikely, especially during joint U.S.-South Korean military drills that end April 30. But the rival Koreas have had several bloody naval skirmishes in disputed Yellow Sea waters and there's some worry among analysts about a provocation after the drills. Observers say Tuesday's statement by the North Korean army's Supreme Command and other recent bellicose language is partly meant to strengthen internal loyalty to leader Kim Jong Un. Pyongyang is angry over recent U.N. sanctions over its nuclear test and says Washington and Seoul plan to invade.