The South Korean defense minister and other officials have acknowledged that they learned of Kim’s death at the same time Pyongyang’s state media told the world on Monday. The admission has caused anger among many South Koreans worrying Kim’s death might trigger instability on the Korean Peninsula.

The Democratic Party said Wednesday that President Lee Myung-bak must fire officials responsible for the fiasco. The Dong-a Ilbo says in an editorial that intelligence on North Korea is directly linked to national security.

Meanwhile, North Korea has tightened security in cities, put troops on alert and won loyalty pledges from top generals after leader Kim’s death as it consolidates power behind his anointed heir, South Korean intelligence indicated Wednesday.

Worries around Northeast Asia have risen sharply as Kim’s untested, twenty-something son, Kim Jong Un, rises to power in a country with a 1.2-million troop military, ballistic missiles and an advanced nuclear weapons development program.

South Korea has put its military on high alert. In another sign of border tension, Chinese boatmen along a river separating North Korea and China told The Associated Press that North Korean police have ordered them to stop giving rides to tourists, saying they will fire on the boats if they see anyone with cameras.

Along the Koreas’ border, the world’s most heavily armed, South Korean activists and defectors launched giant balloons containing tens of thousands of propaganda leaflets, a move likely to infuriate the North.

Some of the leaflets opposed a hereditary transfer of power in North Korea. Some showed graphic pictures of former Libyan leader Muammar Qaddafi’s battered corpse and described his gruesome death.

Kim ruled the country for 17 years after inheriting power from his father, national founder and eternal North Korean President Kim Il Sung, who died in 1994. Un entered the public view last year.

Seoul’s National Intelligence Service believes the North is now focused on consolidating Un’s power and has placed its troops on alert since Kim Jong Il’s death, according to South Korean parliament member Kwon Young-se.