Washington ( CNN ) -- The United States has seen no unexpected moves by the North Korean military since the announcement of Kim Jong Il 's death , the chairman of the Joint Chiefs of Staff said Monday . Gen. Martin Dempsey said the United States is remaining `` vigilant '' in the wake of the death of the North Korean leader . In the first extended on the record comments from a senior U.S. official , Dempsey told a small group of reporters he was awakened overnight to receive the news and immediately joined in an inter-agency phone call of high levels officials to discuss the situation . Dempsey said the call centered on identifying the key military and intelligence indicators that the U.S. would need to watch for any early warning of instability in the regime . Though Kim died on Saturday , U.S. officials only learned of his death from North Korean television on Sunday night . `` The chain of command military and civilian very quickly coalesced around the fact that Kim Jong Il had died , '' Dempsey said . `` We quickly established a network of leaders to discuss this issue and to determine what we could do to contribute to understanding what might happen next . '' U.S. Defense Secretary Leon Panetta spoke with his South Korean counterpart , Kim Kwan-Jin , on Monday morning , said Pentagon spokesman George Little . `` He made it clear that the United States stands with the Republic of Korea in this time of uncertainty , '' Little said . `` Both men agree it is critical to remain prudent in regards to all matters relating to our security posture there , and pledge to keep one another informed in the coming days . Both men agree this is a delicate time , and they need to closely monitor developments in North Korea . '' So far there are no signs of movement of troops or weapons by the North Koreans , Little said . This summer , the commander of American troops in South Korea told Congress that the United States does not believe Kim Jong Un will differ much in decision making from his father or in adjusting the country 's strategic priorites . However , Gen. James Thurman warned of the wildcard of having such a young , inexperienced leader . `` Kim Jong-un 's youth and inexperience increase the likelihood of miscalculation , as does the imperative for him to establish credibility with the military hardliners he needs to support succession , '' Thurman told the Senate Armed Services Committee in a written answer . Dempsey said Monday that the U.S. Pacific Command has reported it has sufficient intelligence assets in the area to keep surveillance on North Korea , but it may shift some capabilities to the peninsula from where they are currently located in the region . U.S. troops in South Korea are not on any heightened state of alert , U.S. military officials said . `` The commander continually assesses our security level and makes adjustments as necessary . But we 're operating under what 's called 'normal armistice conditions . ' In other words , the level of readiness is as it is on any given day , '' Jennifer Buschick , spokeswoman for U.S. Forces-Korea , told CNN . U.S. Forces-Korea 's official website lists the current Force Protection level as `` Bravo , '' with some selected measures at a more heightened `` Charlie '' level . That means they 've stepped up patrols of bases , tightened gate security and ordered troops to pay special attention to `` designated vulnerable points '' both on and off base . But these measures were in place before Kim Jong Il 's death , along with a recent reinstatement of an overnight curfew for U.S. troops in South Korea . Separately , a senior American military official says the test-firing of two short-range missiles by North Korea was expected and not considered related to the current situation . `` There are strong indications ( the missile test ) was pre-planned , and there is no nexus to the death of the North Korean leader , '' the military official said .
No sign of movement of troops or weapons , general says . U.S. defense secretary speaks with South Korean counterpart . - North Korea fires a ballistic missile from its east coast into the sea off Japan. North Korea conducts missile test launch ; West not alarmed .