COSTELLO: North Korea is again ramping up military tensions with live fire drills along this disputed maritime border South Korea. Pyongyang notified Seoul ahead of the exercises and South Korea warned it would return fire if any shells landed in its territory. The drills come amid mounting suspicion that the North is poised for another nuclear test. CNN's Andrew Stevens reports from Seoul, South Korea.</s>ANDREW STEVENS, CNN CORRESPONDENT: Another day of high tensions on the Korean peninsula, North Korea firing some 50 artillery shells into its own waters in the west sea close to the disputed maritime border between the two Koreas. South Korea responding by putting all arms of its military on high alert. It didn't reach the same stage as the last live firing exercise by North Korea last month, which saw North Korean shells dropping into South Korean territory and the South Koreans responding with live fire of their own. It does underline the continued provocative actions being taken by North Korea in the wake of the visit by the U.S. President, Barack Obama, to Seoul just last week. This disputed maritime area remains a flash point in relations between the two Koreas. Four years ago a South Korean naval vessel sunk in the area. The South Koreans claimed it was through North Korea action although the North Koreans have denied that. Also in the same area, an island was shelled four years ago killing several residents so tensions remain very high here in Seoul. There is still a small chance the North Koreans may continue a night live firing exercise which could happen in a few hours from now. Andrew Stevens, CNN, Seoul, South Korea.</s>COSTELLO: Andrew Stevens reporting. The next hour of CNN NEWSROOM starts now.
North Korea Conducts Live Fire Drill