SEOUL (Reuters) - North and South Korea traded blame Thursday for the breakdown of military talks as a stalemate emerged over the starting point for negotiations. North Korean state media blasted what it said was the South's "impudent approach" to the talks, saying it would not take part in any more discussions until Seoul showed it wanted to improve ties and was willing to discuss security issues concerning both sides. The South said that the offer for senior level talks still stood, but demanded dialogue focus on the two attacks last year which killed 50 people, and that Pyongyang bear responsibility. Analysts said the breakdown Wednesday was inevitable as both sides came to the negotiating table with different issues, adding the collapse was typical of past sputtering inter-Korean dialogue. "This could go on for some time, which would be useful if for no other reason that North Korea is unlikely to resort to drastic measures as long as talks are under way or are likely," said Ken Boutin, a North Korea expert at Australia's Deakin University. The United States, which has nearly 30,000 troops in South Korea, said it hoped the rivals could work out their differences and resume talks as soon as possible to reduce tensions on the divided peninsula. China, the isolated North's main ally and main benefactor, called on the two sides to maintain contact and dialogue. The preliminary talks, the first inter-Korean meeting since the North's attack on the southern island of Yeonpyeong in November, broke down over procedural issues, including the agenda and the rank of participants at their next meeting. Both sides accused the other of walking out of the talks. "In a situation where (they) do not wish for improvement of North-South relations and are refusing dialogue itself, our military and people no longer feel the need to be associated with the South," a communique from the delegates carried by the KCNA state news agency said. The North's reaction was in stark contrast to its almost daily calls for dialogue since the start of the year. South Korea said the North's delegates stood by their stance that Pyongyang had nothing to do with the sinking of the South's Cheonan warship in March and that it shelled the island of Yeonpyeong in November out of self-defence. The North insisted that discussions about the attacks should only be taken up at the senior level, KCNA said. It added that any talks should also address its concerns about the South's "provocations," including military drills.