SEOUL (AFP) - North Koreas ailing Kim Jong-Il has named his youngest son to succeed him eventually as leader of the communist state, which appears to be preparing another volley of missiles, reports said Tuesday. The Norths missile launches have defied international condemnation of its weapons programme, after its tested a nuclear bomb last week, and analysts believe Kim may be trying to bolster his authority ahead of a succession. There has been intense speculation about who would succeed North Koreas Dear Leader since he was reported to have suffered a stroke last August. Kim, now 67, is thought to have since recovered and resumed most of his duties. South Koreas intelligence services have received word that Kim has nominated 26-year-old Jong-Un to succeed him, a South Korean lawmaker briefed by intelligence officials said Tuesday. Little is known about Jong-Un, but the Swiss-educated basketball fan has been described as a chip off the old block. Jong-Un is known to have the potential to become a strong, ruthless leader. He has a take-charge personality, Cheong Seong-Chang, a North Korea expert at the Sejong Institute, told AFP. According to reports, North Koreans are being taught new songs aimed at instilling loyalty to the next leader, addressing Jong-Un as General Kim. Jong-Un was born to the leaders third wife, Ko Yong-Hi, who reportedly died of breast cancer in 2004. Jong-Un was educated at an international school in Switzerland. Kims eldest son-Jong-Nam, 37, who was born to a different mother-apparently spoiled his prospects of becoming leader after being deported from Japan in 2001 for trying to enter the country on a forged passport. Reports of Jong-Uns nomination come with South Korean and US forces on heightened alert after the North threatened an attack when Seoul joined a US-led initiative to stop the spread of weapons of mass destruction. South Koreas Yonhap news agency reported Tuesday that the North seems to be preparing to test-fire several medium-range missiles from its southeast coast. Tensions have been running high since the North tested a nuclear bomb for the second time on May 25. It then launched a series of short-range missiles and renounced the 1953 truce that ended fighting in the Korean war. South Koreas navy stepped up its defences near the tense sea border with North Korea Tuesday, sending in a high-speed patrol boat armed with guided missiles and vowing to punish any attacking forces. The North is reported to have stepped up naval drills near the western maritime border-the site of deadly skirmishes between the two Koreas in 1999 and 2002 after threatening to attack the South. Pyongyang has warned of self-defence measures in response to any tougher international sanctions for last weeks nuclear test. US and South Korean officials say the North also appears to be preparing to test-fire a long-range missile capable in theory of reaching Alaska. Washington warned North Korea Monday not to fire such a missile, saying it would further worsen tensions. State Department spokesman Robert Wood said a launch would be a clear violation of a UN Security Council resolution approved after Pyongyangs first nuclear test, in 2006. Two US defence officials told AFP in Washington that Pyongyang appeared to have moved a long-range missile to its new launch site at Dongchang-ri along its northwestern coast. But any launch would likely be weeks away given North Koreas technical capacity, said one of the officials, who asked to remain anonymous. South Korean and Southeast Asian leaders Tuesday condemned the Norths nuclear test and missile launches as they wrapped up a summit on the southern resort island of Jeju. President Lee Myung-Bak and the 10 ASEAN leaders in a statement said the actions were clear violations of UN Security Council resolutions and a multi-nation nuclear disarmament pact.