"This is truly an honor for the whole United Nations," Annan said at a news conference, "its Member States, the General Assembly and the Security Council, and especially its dedicated staff around the world. They work hard every day to make the world a more just, more peaceful, and happier place. Many of them risk their lives. They richly deserve this award."

Early Friday morning, as the press gathered in front of his residence, Annan said he was encouraged and gave credit to the UN staff.

"It's a wonderful award," he said. "We are extremely pleased, particularly coming as it does, at this time when we are tacking some very difficult issues around the world. I think this is going to be a great encouragement for me, personally, and for all my colleagues at the United Nations."

Annan said the prize honors and challenges the UN to do better. Later that day, as the UN Staff cheered him on, he praised their efforts. "Our staff are often on the frontlines," he said. "In the past week alone, we have lost about ten colleagues, in Georgia and in Afghanistan, and yet our staff keep at it. You are prepared to go to any corner of the world in the service of peace and the work of the United Nations."

UN staff plastered headquarters with congratulatory signs at every doorway. Later in the afternoon, a beaming Annan was congratulated by the Security Council.

"You congratulated me," Annan said to Richard Ryan, Security Council President, "but I should also congratulate you and all the members of the Council, present and past alike. In awarding the Nobel Peace Prize to the United Nations, the Norwegian Nobel Committee has of course honored the Security Council, which has, under the Charter, the primary responsibility for maintaining international peace and security."

Speaking on behalf of the Security Council, Ryan said: "We consider this to be a wonderful recognition and an extremely timely one, of the absolute importance of the world's peoples; of the United Nation's systems."

He said the award could not have been more timely, and he looks forward to a renewed sense of international "centrality of the UN system."

When asked about President George W. Bush's statement that the UN should play a substantial nation-building role in Afghanistan, Ryan said Afghanistan was the subject of the Security Council's discussion "with extraordinary regularity, and we will continue to do so."

"There is concern among the Member States that the present phase must include a global response and an adequate response to the humanitarian crisis facing Afghanistan and its people," Ryan said.

Annan recently re-appointed Lakhdar Brahimi as his Special Representative for Afghanistan, who will oversee all humanitarian issues in the region. "It would not surprise me if the Security Council were to give us an expanded mandate for Afghanistan," said Annan at a press conference. "First of all, the Afghan people have a role to play in rebuilding their nation. We've been working with them over a long period and I believe that as we move forward, their views and their desires must be respected."

Annan is the second Secretary General to receive the award. Dag Hammarskjold, the UN's second Secretary General, was awarded the prize posthumously in 1961. The UN has been now been awarded the Nobel Peace Prize a total of five different times.

Historically, a number of UN individuals have also been awarded the prize, including US Secretary of State Cordell Hull in 1945 for his leadership in the creation of the UN and Ralph Bunche in 1950, for his role as the UN acting mediator in Palestine which resulted in the 1949 armistice between Israel and Palestine.