UK Prime Minister Gordon Brown has called for a greater international effort to combat what he called the "emergency" of global poverty.
Mr Brown wants world leaders to live up to promises made in 2000 to tackle a range of development issues, including gender equality, education and poverty.
In a speech at the UN, he said the millennium development goals were "a million miles" from being met.
Mr Brown said he wanted to create a "great coalition of conscience".
The prime minister's speech came after he had met UN Secretary General Ban Ki-moon and discussed ways of dealing with the situation in Darfur, Sudan, where, Mr Brown said, over 200,000 people had been killed, two million displaced and four million were receiving food aid.
A resolution, put forward by the UK, France and the US, setting up a peacekeeping force was accepted on Tuesday.
Earlier Mr Brown said the force would "mandate the deployment of the world's largest peacekeeping operation to protect the citizens of Darfur".
About 19,000 African Union-UN troops would be deployed, and it would be backed up by the threat of more sanctions, Mr Brown said.
In his speech Mr Brown focused on trying to find practical ways of meeting the ambitious goals set by world leaders in 2000, stressing the need for co-operation between governments, the private sector, faith groups and individuals.
Not met until 2100
"To address the worst of poverty, we need to summon up the best of humanity, and I want to summon into existence a great coalition of conscience in pursuit of the greatest of causes.
"And I firmly believe that if we can discover a common purpose, there is no failing in today's world, that cannot be addressed by mobilising our strengths, and there's no individual struggle that drags people down that cannot benefit from a renewed public purpose that will lift people up."
Goals include eradicating extreme poverty, achieving universal primary education, promoting gender equality, cutting child deaths and combating diseases.
He said the goal of providing primary education for every child by 2015 would not be met until 2100, while the goal of cutting infant mortality by two thirds would not be reached until 2050 unless action was taken now.
He said the situation had to be declared to be a "development emergency".
John F Kennedy
He said 12 world leaders and 20 business leaders had signed a new "commitment to action" to meet the "emergency".
"I want us to come together as one world. I want us to call an emergency meeting next year at which we report on where we are and what we have to do."
He said scientists, engineers and the medical profession were key to helping reach the goals.
Mr Brown compared the plan to former US President John F Kennedy's 1960 call for an international peace corps.
That was "an international commitment to harness the idealism many felt in the face of threats to human progress and world peace," Mr Brown said.
"Today we should evoke the same spirit to forge a coalition for justice."
"The simple questions that, to paraphrase the words of an American President, we must ask are; If not now, when? If not us, who? If not together, how?"
Mr Brown added: "I believe the scale of the challenge is such that we cannot now leave it to some other time and some other people but must act now, working together."
The speech came a day after Mr Brown's first official meeting as prime minister with President George W Bush.
During the talks, at Camp David near Washington, Mr Bush and Mr Brown renewed pledges to fight terrorism and seek progress in Iraq.
He said both nations had duties and responsibilities in Iraq, and that he would seek military advice before announcing any changes in policy.
The president spoke warmly of the "special relationship" with the UK and said he found Mr Brown a warm, humorous man.
On the issue of Iraq, Mr Brown said: "Our aim, like the United States is, step-by-step, to move control to the Iraqi authorities."
He also denied suggestions that his view of terrorism differed greatly from that of Mr Bush.
Mr Brown added: "We know we are in a common struggle, we know we have to work together, and we know we have to deal with it."