Pyongyang, Dec 21: North Korea has tightened security in cities, put troops on alert and won loyalty pledges from top generals after leader Kim Jong Il'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 Moammar Gadhafi's battered corpse and described his gruesome death.
Kim Jong Il 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.
Kim Jong Un only entered the public view last year and remains a mystery to most of the world.
Seoul's National Intelligence Service believes the North is now focused on consolidating Kim Jong 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.
South Korean military officials, who spoke on condition of anonymity because of office policies that restrict comment on intelligence matters, confirmed that North Korea has ordered its troops to be vigilant but said that doesn't mean they're being moved.
North Korea announced pn Monday that Kim had died of a massive heart attack two days earlier at the age of 69 - although some accounts put his age at 70.
Lawmaker Kwon said the NIS has told the parliamentary intelligence committee, which he chairs, that senior military officials have pledged allegiance to Kim Jong Un, and that more security officers have been deployed in major cities across the country.
Intelligence officials declined to comment.
According to a Defense Ministry report submitted to parliament on Tuesday and leaked to reporters by South Korean lawmakers, some North Korean units conducting winter drills returned to base following the news of Kim Jong Il's death.
It also said official mourning events have begun in a number of front-line bases across the country. The report did not elaborate.
Unification Ministry spokesman Choi Bo-seon said in a briefing Wednesday that the government hasn't spotted particular troop movements in North Korea.
Military officials said they also haven't noticed serious developments.
Initial indications coming out of North Korea suggest the transition to Kim Jong Un has been moving forward.
The young Kim led a procession of senior officials Tuesday in a viewing of Kim Jong Il's body, which is being displayed in a glass coffin near that of Kim Il Sung.
Publicly presiding over the funeral proceedings was an important milestone for Kim's son, strengthening his image as the country's political face at home and abroad.
State media showed video of Kim Jong Un receiving mourners, including foreign envoys, as he stood near his father's body with an honor guard.
He was somber during the greetings, although footage at one point showed him teary-eyed. A report in the North's official Korean Central News Agency did not specify which foreign countries the envoys represented.
According to official media, more than five million North Koreans have gathered at monuments and memorials in the capital since the death of Kim Jong Il. Hundreds of thousands visited monuments around the city within hours of the official announcement that Kim had died.
The North has declared an 11-day period of mourning that will culminate in his state funeral and a national memorial service on Dec. 28-29.
The propaganda leaflets sent into North Korea on Wednesday by South Korean activists are a sore point with the North, which sees them as propaganda warfare. North Korea has previously warned it would fire at South Korea in response to such actions. There were no immediate reports of retaliation, however. South Korean activists vowed to continue sending leaflets.
South Korea's main opposition party, meanwhile, called for the sacking of top intelligence, security and foreign affairs officials for failing to know about the death of Kim Jong Il before it was officially announced.
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 Monday.