North and South Korea' first working-level military discussions for almost two years ended without result Thursday, according to dpa. The South "strongly urged North Korea to admit to, apologize for and punish those responsible for the attack" on one of its warships in the Yellow Sea in March that led to the deaths of 46 sailors, the Yonhap news agency reported quoting a Defence Ministry statement. North Korea said it refused to accept the findings of an international investigation in May that blamed it for torpedoing the corvette Cheonan. The South Korean Defence Ministry's statement also demanded that its Stalinist neighbour "immediately stop its military threats and aggressive behaviours at sea borders." Prior to the talks, the head of the North Korean delegation, Colonel Ri Shin Kwon, said, "All issues should be resolved from the point of a humanitarian view at today's talks." Thursday's meeting took place at the same time as five days of joint naval exercises between the United States and South Korea in the Yellow Sea. They began on Monday and were focusing on anti-submarine drills. Officers from each side met at Panmunjom on the border between the countries at around 10 am (0100 GMT) and the talks lasted roughly two hours. No date was set for future talks, a South Korean Defence Ministry official who did not want to be named said. The sinking of the South Korean ship led to rising tensions on the Korean Peninsula. There have been some signs recently of improving relations with the release of a South Korean fishing boat and the North's proposal of fresh reunions of families separated by the 1950-53 Korean War and division of the Korean Peninsula. Yonhap said, however, that the South Korean military was wary of the provocative actions by the North, followed by talks aimed at winning concessions.