US Secretary of State Hillary Rodham Clinton on Tuesday warned North Korea against following through on a threatened missile launch, saying it would damage its prospects for improved relations with the United States and the world. In Tokyo on her first trip abroad as America's top diplomat, Clinton also stressed US commitment to Japan's security, signed a military deal to advance that and underscored the importance of the alliance by inviting Japanese Prime Minister Taro Aso to Washington next week. Aso, deeply unpopular at home, will be the first foreign leader to visit President Barack Obama at the White House, and the Feb. 24 summit is a sign that the world's two largest economies know they have a special responsibility to deal the global financial crisis, Clinton said. She had hoped to broaden US-Asian relations to include climate change, clean energy and the world's economic woes on her maiden overseas voyage, but North Korea and its increasingly belligerent rhetoric toward its neighbors were clearly at the top of her agenda. Just before she arrived in Japan on Monday, North Korea used the 67th birthday of its leader Kim Jong Il to claim it has the right to "space development" - a term it has used in the past to disguise a long-range missile test as a satellite launch. A day later, Clinton, without prompting, told reporters at a joint news conference with Japanese Foreign Minister Hirofumi Nakasone that such a move would jeopardize the Obama administration's willingness to work for better ties with Pyongyang. "The possible missile launch that North Korea is talking about would be very unhelpful in moving our relationship forward," she said, adding that if Pyongyang wants to end its isolation it also has to fulfill unmet denuclearization pledges made during the Bush administration. "The decision as to whether North Korea will cooperate in the six-party talks, end provocative language and actions is up to them and we are watching very closely," Clinton said, referring to the six-nation talks aimed at getting North Korea to abandon nuclear weapons. "If North Korea abides by the obligations it has already entered into and verifiably and completely eliminates its nuclear program, then there will be a reciprocal response certainly from the United States," she said. "It is truly up to the North Koreans." Those responses include a chance to normalize relations with the United States, formally ending the 1950-53 Korean War with a peace treaty to replace the current armistice, as well as energy, financial and humanitarian assistance for the North Korean people. Clinton also vowed to keep up pressure on the North to resolve Japan's concerns about the status of Japanese citizens abducted by Pyongyang in the 1970s and '80s. She met with relatives of some abductees in a private session at the U.S. Embassy to promise such steps. Many abductee families were angered by the Bush administration's decision last year to remove North Korea from the US list of state sponsors of terrorism as an incentive in the nuclear talks without addressing their concerns. At the meeting, representatives of the families presented Clinton with a letter repeating their disappointment with the step and asked that the Obama administration put North Korea back on the list pending a resolution to the abductee issue. There was no immediate response to the letter from U.S. officials. Clinton said the United States remained firmly committed to the defense of its allies in the region, particularly Japan and South Korea, and signed an agreement with Nakasone to reduce tensions caused by the presence of U.S. troops on Japanese soil. Under the deal, which has been in the works for years, 8,000 Marines now stationed on the Japanese island of Okinawa will be moved to the U.S. Pacific territory of Guam. There are 50,000 American troops in Japan, about 20,000 of them on Okinawa. On the financial crisis, Clinton said the United States and Japan had to work together to formulate an adequate response. "As the first and second largest economies in the world, we understand those responsibilities and we also know the importance of making sure our economies work on behalf of our own citizens," said Clinton. "It is a great responsibility that both Japan and the United States assume." Nakasone agreed. "This is a global financial and economic crisis and therefore all economic powers will need to cooperate with each other and try to resolve the issue in a concerted manner," he said. He said the Obama administration's economic stimulus bill, to be signed by the president Tuesday, was "most meaningful" with its combination of spending and tax cuts and added that Japan was looking at ways to improve its situation. Clinton's invitation to Aso to visit the White House came a day after figures showed the Japanese economy shrank at its fastest rate in 35 years and shows no signs of reversing course anytime soon. It was delivered as Aso's already battered government was dealt another blow when Finance Minister Shoichi Nakagawa announced he would resign due to health problems after facing allegations he was drunk at a recent economic meeting in Rome.