SEOUL, South Korea (AP) -- North Korea pushed forward with preparations to test-fire more missiles in the wake of last week's nuclear test as leader Kim Jong Il moved to anoint his third son as heir to the world's first communist dynasty, reports and experts said Tuesday.
At least four missiles were spotted being readied at North Korean launch pads: a long-range missile on the west coast near China and three to four medium-range missiles on the east coast. U.S. military officials confirmed the preparations of a Taepodong-2 capable of striking the U.S., and the Yonhap news agency cited a lawmaker briefed by defense officials for the east coast launch.
North Korea was also strengthening its defenses and conducting amphibious assault exercises along its western shore - possible preparations for skirmishes at sea, reports said. South Korea deployed a guided-missile, high-speed boat to the area to stamp out any provocations, the navy said.
As tensions continued to escalate - with U.N. ambassadors discussing a new Security Council resolution in response to the nuclear test - the regime reportedly began paving the way for Kim's 26-year-old son, Jong Un, to eventually take over as leader of the nation of 24 million people.
A succession announcement went out after the May 25 underground nuclear test to top Workers' Party, military and government officials, South Korea's Dong-a Ilbo and Hankook Ilbo newspapers said Tuesday, and the North was already hailing the son as "our Commander Kim" in a new song being taught to the people, the Dong-a Ilbo said.
South Korea's National Intelligence Service said it cannot confirm the reports.
Analysts say the recent saber rattling is part of a campaign to build unity and support for the eventual successor to 67-year-old Kim Jong Il, who reportedly suffered a stroke last August.
After disappearing from the public eye for weeks last fall, Kim made his first state appearance in months at the delayed opening session of the country's new legislature April 12, grayer and thinner and limping slightly.
Kim was believed to want to name a successor by 2012 - the centenary of the birth of his father, North Korea founder Kim Il Sung - and the regime undertook a massive campaign last year to prepare the country for the 100th anniversary celebrations.
The April 5 launch of what North Korea claimed was a successful bid to send a communications satellite into space was believed part of the campaign, to show off the country's scientific advancements. But in an abrupt shift in plans, the regime stepped up the pace and in early May launched a "150-day battle" urging North Koreans to work harder to build up the country's economy.
"Before 2012, North Korea must convince the army and the public that Jong Un is the best successor," said Atsuhito Isozaki, assistant professor of North Korean politics at Tokyo's private Keio University. "To pave the way for Jong Un's leadership, it is highly likely that North Korea will turn recent nuclear and missile tests into his achievements."
Analyst Cheong Seong-chang of the Sejong Institute, a South Korean security think tank, noted that the "politically driven" campaign is set to end in early October, about the time of the anniversary of the founding of the ruling Workers' Party. He said North Korea could hold a national convention then - its first in nearly 30 years - to formally announce the successor.
Cheong noted that in the 1970s, Kim Il Sung, known as the "Great Leader," arranged for his son to take credit for a "70-day battle" before he was tapped in 1974 as his father's successor. The succession decision was made public at a 1980 convention, and Kim Jong Il - the "Dear Leader" - formally assumed leadership upon his father's death in 1994.
"Since Kim had a stroke last year, North Korea appears to be in a hurry in naming his successor," Isozaki said.
Kim has three sons, and many believe the youngest has the best chance of succeeding the authoritarian leader, possibly with the backing and guidance of his uncle, Jang Song Thaek, a member of the all-powerful National Defense Commission who has strong military and political connections.
The eldest son, Jong Nam, 38, had long been considered the favorite to succeed his father - until he was caught trying to enter Japan on a fake passport in 2001. He reportedly told Japanese officials he wanted to visit Tokyo Disneyland.
Kim considers the middle son, Jong Chol, too effeminate for the job, according to a Japanese sushi chef who said he served Kim Jong Il for many years.
Little is known about Jong Un, the second son of former dancer Ko Yong Hi, who died in 2004.
He studied at the International School of Berne in Switzerland in the 1990s under the pseudonym Pak Chol, learning to speak English, German and French, the Swiss weekly news magazine L'Hebdo reported earlier this year, citing classmates and school officials.
A classmate recalled him as shy and introverted but an avid skier and basketball player who was a big fan of the NBA star Michael Jordan. The sushi chef, who goes by the pen name Kenji Fujimoto, said in a 2003 memoir that Jong Un looks and acts just like his father and is the leader's favorite.
South Korean lawmaker Park Jie-won, a member of the intelligence committee, told a radio show Tuesday that the spy agency briefed lawmakers that the regime already is "pledging its allegiance to Kim Jong Un," according to an transcript provided by his office.
The missile and nuclear tests also are part of a campaign to grab Washington's attention at a time when Kim has two other pressing issues that must be resolved before his health worsens: establishing security by normalizing relations with the U.S. and strengthening the economy, Cheong said.
Satellite images indicate the North has transported a long-range missile to the new Dongchang-ni facility near China, a Yonhap report said. A U.S. official confirmed that the missile was moved by train and said it could be more than a week to liftoff. He spoke on condition of anonymity because the issue involved intelligence.
The Chosun Ilbo newspaper also said the North may have manufactured up to four more long-range missiles.
On the east coast, vehicles mounted with at least three mobile launchers were spotted at Anbyon, Yonhap said Tuesday, citing an unnamed government official.
North Korea also has custody of a South Korean worker detained at a joint industrial complex at the border. He has been transferred to Pyongyang, Yonhap said Tuesday.
Associated Press writer Shino Yuasa in Tokyo contributed to this report.