UNITED NATIONS - The U.N. Security Council on Monday formally nominated South Korean Foreign Minister Ban Ki-moon to succeed Kofi Annan as United Nations secretary-general, all but assuring that the quiet diplomat will become the eighth chief in the world body's 61-year history. (Key quotes about the UN secretary-general nominee )

South Korean Foreign Minister Ban Ki-moon adjusts his glasses during a press conference at the Foreign Ministry in Seoul, Monday, Oct. 9, 2006. Ban expressed gratitude Monday for being nominated as U.N. secretary-general and said he would work to resolve the crisis over North Korea's nuclear program after the communist country conducted an unprecedented atomic test. [AP]

What would have been an event of major significance - Ban will become one of the world's best-known and most influential diplomats over his five-year term was overshadowed by North Korea's claim that it had conducted a nuclear test.

"This should be a moment of joy. But instead, I stand here with a very heavy heart," Ban said at a news conference in Seoul. "Despite the concerted warning from the international community, North Korea has gone ahead with a nuclear test."

Ban, who participated in six-party talks with the North in 2005, vowed to help resolve the North Korean nuclear crisis after he becomes secretary-general. He must be approved by the 192-nation General Assembly, which has never rejected a Security Council nomination.

Japan's U.N. Ambassador Kenzo Oshima asked the General Assembly to act promptly to give final approval to Ban so he can have a sufficient transition before taking over as U.N. chief on Jan. 1, after Annan's second five-year term ends.

"I think the fact that the candidate is currently foreign minister of the Republic of Korea is an asset in dealing with the situation in the Korean peninsula that we are now facing," he said.

Some diplomats speculated that North Korea may have conducted the test when it did partly to signal its disapproval for Ban. The North has not publicly commented on his bid but has accused him of blindly following the U.S. line by urging the North to resume negotiations and give up the atomic weapons program.

Normally the 15-member council would vote on a nomination, but Britain's Ambassador Emyr Jones-Parry suggested in Monday's meeting that Ban be approved by acclamation, done when there are no dissenting votes. The idea was greeted with applause from the other ambassadors, diplomats who attended the meeting said.

Unlike in previous years, Ban's selection was marked by an absence of rancor or political infighting. He was the front-runner in all four informal polls the Security Council conducted, never getting fewer than 13 votes in favor of his candidacy.

The final straw poll last week revealed that he had the support of all five veto-wielding members of the council, and the remaining five candidates quickly left the race.

U.S. State Department spokesman Sean McCormack said in a statement that Ban "is the right choice to lead the United Nations at this pivotal time in its history." U.S. Ambassador John Bolton called Ban's selection "a very significant event."

"It's really quite an appropriate juxtaposition that today 61 years after the temporary division of the Korean peninsula at the end of World War II, we're electing the foreign minister of South Korea as secretary-general of this organization and meeting as well to consider the testing by the North Koreans of a nuclear device," Bolton said.

Ban's selection now will give him more than two months to prepare to lead an organization that has deployed 92,000 peacekeepers around the world and has annual operating budget of $5 billion. Fighting hunger, assisting refugees and slowing the spread of HIV/ AIDS are all programs that fall under the secretary-general's purview.

Annan "warmly welcomes" the decision nominate Ban, whom he has the "highest respect for," U.N. spokesman Stephane Dujarric said. Annan, who won the Nobel Peace Prize as secretary-general in 2001, urged the General Assembly to make a decision on Ban as soon as possible.

Ban has been South Korea's foreign minister for more than 2 1/2 years and served as national security adviser to two presidents - jobs that focused on relations with the North. He has served as a diplomat for nearly 40 years, including previous stints at the U.N. and in Washington.

He had courted Security Council nations aggressively during his campaign and gave numerous speeches to make himself better known and counter the impression that he was too quiet or humble to inherit the job.

Yet the actual selection process was mostly conducted behind closed doors, adhering to a tradition that has drawn criticism from some members of the General Assembly and non-governmental organizations that believe the job is too important to be awarded in such secrecy.

Nonetheless, diplomats said they believed Ban was the right man to lead the organization that many believe is in desperate need of reform. Its procurement department has been saddled by allegations of corruption and mismanagement, while many world leaders believe its most powerful organ, the Security Council, must be revamped to reflect the realities of 2006 and not 1945, when it was created.

"We think that he has all those qualities that are necessary for a secretary-general that are probably hard to differentiate and count on your hands," Russia's U.N. Ambassador Vitaly Churkin said. "This is the person who, with our support, can tackle this difficult work."