UN Secretary-General Ban Ki-moon vowed to speed up aid efforts to help stricken Haitians as he toured the devastated capital and flew home bearing the UN's dead.
"I am here to say we are with you. You are not alone. This is a tsunami-like disaster," Ban told a press conference after flying over the ruined city in a helicopter.
The UN chief met with President Rene Preval and had an emotional reunion in Port-au-Prince with Michele Montas, a Haitian who until late last year was his spokeswoman.
Later Sunday, Ban flew back to New York bearing the bodies of some of the 40 UN staffers killed when the UN mission in Port-au-Prince collapsed in the quake, in what has become the global body's worst tragedy ever.
"I am going to Haiti with a very heavy heart to express solidarity and full support of the UN to the people of Haiti," Ban told journalists at the start of his day-long trip.
Some 330 UN workers are still missing in the rubble of the UN mission.
But in what Ban called "a small miracle" a Danish UN worker was pulled from the ruins just after the UN chief had toured the site struck by Tuesday's 7.0-magnitude quake.
Jen Kristensen was pulled out of the remains of the UN's six story headquarters, where the walls have become a sarcophagus for so many, without a scratch on him.
UN firefighter Neville Fouche expressed his amazement at the rescue: "Five days after the earthquake! How is it possible? It is simply a miracle," he said.
Ban said the three top priorities were: to save as many people as possible, to bring emergency humanitarian aid in the form of water, food and medication, and to coordinate the massive aid effort.
The UN has noted that at least local government structures remained after the 2004 tsunami hit Indonesia's Aceh province, but in the Haiti town of Leogane, for example, all public services were lost in the earthquake.
Between 20,000 and 30,000 people are thought to have died in that town alone, an indication of the horrific scale of the catastrophe beyond Port-au-Prince.
The Haitian government said Sunday that it had already buried some 70,000 bodies in mass graves, and was declaring a state of emergency until the end of the month.
Ban came face-to-face with the human toll when he toured a makeshift tent city of 50,000 people which has sprung up on the open air Champs de Mars square next to the collapsed presidential palace.
"We need food, we need shelter, we need work," angry and frustrated Haitians shouted.
Ban urged them to be patient, saying help was coming, and warned against rioting.
The fact-finding mission was aimed at assessing the Caribbean nation's needs and attempting to boost the shattered morale of the Brazilian-led United Nations Stabilization Mission in Haiti, MINUSTAH.
Among the dead being mourned by the UN is the head of the mission civilian chief Hedi Annabi, his Brazilian deputy Luiz Carlos da Costa and acting police commissioner, Doug Coates of the Royal Canadian Mounted Police.
Ban has sent Edmond Mulet, a top UN peacekeeping official and Annabi's predecessor, to Port-au-Prince to take charge of MINUSTAH in an interim capacity.
Later he and Mulet took part in a ceremony to remember the UN's dead, and in a sad symbolic move, Ban was handed the flag from the UN headquarters to take back to New York with him.
The United Nations on Friday appealed for 562 million dollars from the world community to help three million quake victims in the western hemisphere's poorest country for the next six months.
The money is to be used for urgently needed food, water and sanitation, medical supplies, tents and blankets, logistics and education.
Ban last toured Haiti with former US president Bill Clinton in March 2009 to urge the international community to aid the island nation after it was battered by hurricanes the previous year.
