ISLAMABAD -- Weeks of lingering hopes for a limited improvement in relations between South Asia's two large nuclear-armed neighbors, India and Pakistan, were shattered in less than two minutes when an Indian fighter jet shot down a Pakistani naval patrol aircraft.

All the 16 passengers aboard the Pakistani plane were instantly killed. Delhi justified the action as a necessary step to secure its territorial limits from foreign intrusion, while Islamabad denied that the aircraft had ventured over hostile terrain. While describing the shooting as a "cowardly act," Pakistan promised to do everything possible to preserve its territorial integrity.

Given South Asia's hostile environment, such exchanges are hardly comforting for the rest of the world, which is eager to see the two nuclear-armed countries stay away from the prospect of war. Despite international calls urging both sides to show restraint, the latest incident is unlikely to be the last of its kind as the world's two newest nuclear powers continue to score military points. Earlier this summer, the two countries came to the brink of war, despite international calls to show restraint, amid intense fighting along the border of the disputed state of Kashmir.