SEOUL, South Korea - North Korea conducted at least one short-range missile test Monday, the same day it announced the death of leader Kim Jong Il, South Korea's Yonhap news agency reported.
Two South Korean military officials said they couldn't immediately confirm the report, saying to do so would breach a policy of not commenting on intelligence matters.
Both said any firing would be part of a routine drill and have little relation to Kim Jong Il's death. They both spoke on condition of anonymity, citing policy.
Yonhap cited unidentified government and military officials as saying the test occurred off the east coast.
North Korea is urging its people to rally behind Kim Jong Il's young son and heir-apparent Kim Jong Un, as the world watches warily for signs of instability in a nation pursuing nuclear weapons.
South Korea has put its military on high alert against the North's 1.2 million-strong armed forces. President Barack Obama agreed by phone with South Korean President Lee Myung-bak to closely monitor developments. While U.S. officials said there was concern in Washington that Kim's death may spark changes in military postures of North and South Korea, they were hopeful calm would prevail.
"There are factions within the North Korean military that might take those steps to assert themselves. But you don't know. What you don't want right now is an escalation in the peninsula," Bill Richardson, former New Mexico governor and U.S. ambassador to the United Nations,. "I think South Korea is playing it right, playing it cool. Yes, you go on military alert, but just watch things as they develop and hope that this transition is as stable as possible so you can resume some kind of dialogue with North Korea again. I think it makes sense to engage them, rather than isolate them, but you've got to watch things in the next 48 hours. I think what the North Korean military commanders say the next day will be critical."
Suspension of uranium enrichment by North Korea had been a key outstanding demand from both the U.S. and South Korea of the North, which has tested two atomic devices in the past five years. Recent food talks in Beijing yielded a breakthrough on uranium enrichment, the sources said.
Kim's death was announced by state media in a "special broadcast" from Pyongyang late Sunday. The report said Kim died of a heart ailment on a train due to a "great mental and physical strain" on Dec. 17 during a "high intensity field inspection." North Korea will hold a national mourning period until Dec. 29. Kim's funeral will be held on Dec. 28, it said.
The U.S. officials stressed that North Korea's past behavior has been notoriously erratic, making predictions about its intentions difficult. However, they said they believed there would not be significant changes in North Korean policies under Kim's son and heir apparent Kim Jong Un until at least after the mourning period ends.
North Korea is preparing for next year's 100th anniversary of the birth of its founder Kim Il Sung Kim Jong Il's father. The preparations include massive construction projects throughout the capital as part of Kim Jong Il's unfulfilled promise to bring prosperity to his people.