SEOUL (Reuters/AFP) - North Korea denounced upcoming joint South Korean-US military drills and said it would wipe out the countries with nuclear weapons if they threatened the communist state, its KCNA news agency said on Sunday. A spokesman for Pyongyangs military denounced the exercises as manoeuvres for a nuclear war against North Korea. South Korean and US forces will on Monday (today) start joint computer simulation and communication drills that come in the wake of rare conciliatory moves by Pyongyang, which this month released two US journalists and a South Korean worker it had held captive. North Korea regularly denounces joint drills as a preparation for invasion and nuclear war. Should the US imperialists and the Lee Myung-bak group threaten the DPRK (North Korea) with nukes, it will retaliate against them with nukes, KCNA quoted a military official as saying. Lee Myung-bak is South Koreas President. If they threaten the DPRK with missiles, it will react to them with missiles, he said. The US imperialists and the Lee Myung-bak group should clearly understand that it is the iron will and resolute stand of the Korean Peoples Army to go into action anytime to mercilessly wipe out the aggressors, the official said. The spokesman added: If they tighten 'sanctions and push 'confrontation to an extreme phase, the DPRK will react to them with merciless retaliation of its own style and an all-out war of justice. The warning from Pyongyang came in a statement issued on Saturday by the spokesman at the inter-Korean border village of Panmunjom. It was published on Sunday by the official Korean Central News Agency. Seoul and Washington have denied having any plans to invade North Korea, saying the drill, from August 17-27, is defensive in nature. US and South Korean military authorities last month informed North Korea of their plan to hold the joint military drill, which will involve 10,000 US soldiers and an unspecified number of South Korean troops. They said the Ulchi Freedom Guardian (UFG) annual military drill involves computer-simulated war games designed to improve the allies ability to defend South Korea from attack. North Korean leader Kim Jong-Il had a cordial meeting Sunday with a top South Korean business tycoon who had secured the release of an employee detained by the communist regime, state media said. Hyundai Group chairwoman Hyun Jung-Eun had travelled to the North to seek the release of Yu Seong-Jin, days after former US president Bill Clinton went to Pyongyang to meet Kim and win a pardon for two American journalists. After negotiating Yus release Hyun extended her stay in North Korea for a fifth time on Sunday in an apparent attempt to meet Kim, an official and her company said. Hyundai employee Yu Seong-Jin returned home Thursday evening after more than four months in captivity, raising hopes of better cross-border relations after 18 months of bitter hostility from North Korea. Hyun presented an unidentified gift to Kim at the meeting ahead of a luncheon the Norths leader hosted for the industrialist and her party, Pyonyangs official Korean Central News Agency said. Kim Jong-Il expressed thanks for this and had a cordial talk with her in an atmosphere of compatriotic feelings, the agency said. Also at the meeting was Kim Yang-Gon, chairman of the Korea Asia-Pacific Peace Committee, who is in charge of cross-border relations, it added. The agency, however, gave no details on what Kim and Hyun discussed, and simply said the Norths leader with deep emotion recalled Hyuns predecessors at Hyundai Group, which spearheaded inter-Korean business. The Kim-Hyun meeting shows that the North treats the individual Hyundai Group cordially, but not South Korea in general. It does not necessarily herald a quick thaw in frosty inter-Korean relations, Koh Yu-Hwan, a North Korean expert and professor at Seouls Dongkuk University, told AFP. Hyun was also in North Korea to discuss restarting tours which were shut down amid worsening political tensions. The Hyundai chairwoman, whose group pioneered inter-Korean joint business projects, met Kim in 2005 and twice more in 2007 to arrange tourist trips to North Korea.