Secretary-General Ban Ki-moon joined the United States Monday in ratcheting up pressure on North Korea by recommending U.N. Security Council action for a torpedo attack that kill 46 South Korean sailors. The South Korean U.N. chief called the evidence 'overwhelming and deeply troubling' that Pyongyang was responsible for the March 26 sinking of the Cheonan in the Yellow Sea off the west coast. He urged the 15-nation council, as the U.N.'s powerful body, to respond to one of South Korea's worst military disasters since the 1950-53 Korean War. The United States announced Monday it would conduct joint naval exercises with the South Koreans. 'My sincere hope is that this will be dealt with by the Security Council, and they should take necessary measures on this matter,' the U.N. chief told a news conference at U.N. headquarters. 'There must be some major step to be taken. The evidence is quite compelling. There is no controversy.' Ban came out hard-hitting about the torpedo that an international team of investigators concluded last week was fired from a North Korean submarine and tore the South Korean ship in two. But he repeatedly said he was pressing his global duties, rather than acting as a partisan because he is a former South Korean foreign minister. 'I try to be very objective and fair, reasonable,' he said. Any action by the 15-nation Security Council, the U.N.'s most powerful body, may depend on the outcome of negotiations between the U.S. and China, the veto-wielding permanent seat holder on the council with the most sway over North Korea. Indeed, already some 'very active consultations have been taking place among key members of the Security Council' on the ship sinking, Ban said. The U.N. chief's comments echo those of U.S. President Barack Obama, who offered his full support for South Korea's moves. The U.S. and South Korea are planning two major military exercises off the Korean Peninsula in a display of force intended 'to deter future aggression' by the North Korea, the White House said Monday. South Korean President Lee Myung-bak outlined economic and diplomatic measures against the impoverished Communist nation, including halting some trade. Ban said the team's evidence 'is overwhelming and deeply troubling. I fully share the widespread condemnation of the incident.' He did not elaborate on which details of the evidence he was referring to. Ban said it was 'particularly deplorable' that North Korea's attack occurred while talks to rid the Korean Peninsula of nuclear weapons are stalled. China, Japan, Russia, South Korea and the U.S. have been trying to persuade North Korea to give up its nuclear weapons in six party talks. The North quit the negotiations last year. 'Such an unacceptable act by the DPRK runs counter to international efforts to promote peace and stability in the region,' Ban said. Ban, like South Korean President Lee Myung-bak, called the attack the latest in a series of provocations from the North. Unfortunately, there have been several such provocations during the last four or five decades,' he said. 'This is one of the most serious, I believe, provocations in recent days.' South Korea, in response, is now aiming to strike Pyongyang financially by cutting hundreds of millions of dollars in trade with isolated North Korea, which is in desperate need of hard currency. South Korea has been North Korea's No. 2 trading partner, behind China. 'You have seen such widespread condemnation from many countries around the world, and the evidence, the facts, lead out by this joint international investigation team were very compelling and overwhelming, Ban added. 'I have been personally very much troubled by what had happened there.' 