WASHINGTON -- The American aircraft carrier USS Kitty Hawk and a Chinese nuclear submarine squared off in international waters off China's coast this fall in a maritime encounter that demonstrated the growing potential for naval conflict between the United States and China, the Los Angeles Times has learned.


Shortly after the incident, which occurred in the Yellow Sea on Oct. 27 to 29, China served notice through a U.S. military official in Beijing that the next time such a situation arises, China's orders will be to shoot to kill, Pentagon officials confirmed this week.


Although in the end no shots were fired in the high-seas confrontation, U.S. officials acknowledge that it was serious.


The captain of the Kitty Hawk dispatched S-3 anti-submarine warfare aircraft to drop sonic devices designed to track the nuclear sub.


Chinese Air Force jet fighters scrambled and flew within sight of the American planes.


Finally, after the Chinese submarine withdrew to its base at the Chinese naval port of Qingdao, the U.S. aircraft carrier was pulled out of the area.


The Kitty Hawk, whose home port is San Diego, had been used earlier to project American power in the Persian Gulf and off the coast of Somalia.


Then it was transferred last July to an American naval base in Japan.


The encounter underscored the growing maritime tensions between the U.S. Pacific Fleet and China, which is now rapidly developing a blue-water navy.


U.S. officials say they found the nuclear submarine in open waters where they had rarely spotted Chinese vessels before.


There had been one other instance, in early September, in which U.S. Navy ships encountered a Chinese submarine, but that episode ended much more quietly.


The previously unreported incident also highlights some of the gunboat diplomacy involving the United States, China and North Korea that surrounded the U.S.-North Korean nuclear agreement reached Oct. 17.


In September, the USS Kitty Hawk was dispatched to waters off North Korea in what a U.S. military official acknowledged was a show of force intended to influence nuclear negotiations in Geneva., in roughly the same way that the dispatch of American troops had forced General Raoul Cedras and his military regime to give up power in Haiti.


Pentagon officials have been watching as China has rapidly increased its naval strength, with the aid of some purchases from what was once the Soviet Union's navy.


U.S. officials said this week that the Chinese Navy recently ordered four Kilo-class conventional submarines from Russia, and that one of these left St. Petersburg very recently for refitting in another port.


The nuclear submarine encountered by the Kitty Hawk is one of five operated by China's navy. It is 110 meters long, weighs 5,000 tons, and carries torpedoes, U.S. officials say. U.S. intelligence officials say the nuclear submarines do not often operate in open ocean, but their operations have picked up lately.