South Korea's Yonhap news agency says North Korea has conducted a short-range missile test on the day the country announced the death of leader Kim Jong Il.
South Korean military officials said Monday they couldn't immediately confirm the report. Yonhap cited unidentified government officials as saying the missile 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. The world is watching 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.
The North's official Korean Central News Agency says the country "must faithfully revere respectable comrade Kim Jong Un."
North Korea on Monday urged its 24 million people to rally behind Kim Jong Un as it mourns the death of supreme leader Kim Jong Il.
The North's neighbors, meanwhile, are mindful of North Korea's nuclear weapons programs and 1.2 million-strong armed forces. South Korea has put its military on high alert.
Kim Jong Il, North Korea's mercurial and enigmatic leader, has died. He was 69.
Kim's death was announced Monday by the state television from the North Korean capital, Pyongyang.
Kim is believed to have suffered a stroke in 2008 but appeared relatively vigorous in photos and video from recent trips to China and Russia and in numerous trips around the country carefully documented by state media. The leader, reputed to have had a taste for cigars, cognac and gourmet cuisine, was believed to have had diabetes and heart disease.