South Korean Foreign Minister Ban Ki-moon has been unanimously chosen to lead the UN for the next five years and accepted the position saying the world body needed to promise less and deliver more.
The 62-year-old career diplomat will take over from Ghanian chief Kofi Annan in January and will become the world body's eighth secretary-general and the first Asian UN chief since U Thant of Burma led the organization from 1961 to 1971.
"I am deeply honored to become the second Asian to lead the organization," Ban told the General Assembly after his nomination on Friday.
"The true measure of success for the UN is not how much we promise, but how much we deliver for those who need us most," he said. "The UN is needed now more than ever before."
Ban, a mild-mannered figure, has played key roles both as South Korea's foreign minister and earlier as Seoul's ambassador to the UN in trying to resolve the long-standing North Korean nuclear crisis.
On Friday he outlined fighting poverty, HIV/AIDS, environmental degradation and protecting human rights as among the priorities of his tenure along with containing the spread of weapons of mass destruction and combating terrorism.
The UN body is under increasing pressure to reform, notably from its biggest financial backer and host the US, but Ban hinted that reforms would only come at an appropriate time.
"We reform not to please others, but because we value what this organization stands for. We reform because we believe in its future. We cannot change everything at once. But if we choose wisely, and work together trans-parently, flexibly and honestly, progress in a few areas will lead to progress in a few more," he added.
The EU and US led the congratulations, with US Ambassador to the UN John Bolton saying: "We believe he is the right person to lead the UN at this decisive moment in its history, particularly as the UN struggles to fulfil the terms of the reform agenda that world leaders agreed to last fall."
US President George W. Bush welcomed the appointment, with the White House saying in a statement that Ban assumed his role at a time of great challenge.
"We will rely on his leadership to help steer the UN through the reforms already underway, and to propel the organization even further on the path of reform," the White House said.
Ban's appointment was a mere formality after the powerful 15-member Security Council recommended him as Annan's successor on Monday, an event overshadowed by North Korea declaring it had conducted a nuclear test.
His election coincides with a major international crisis over North Korea's nuclear program and he somberly welcomed his nomination by the Security Council on Monday just after Pyong-yang's nuclear announcement.
"This should be a moment of joy. But instead, I stand here with a very heavy heart," he said.