Haiti anger at quake chaos

And the destruction of the United Nations headquarters and many government buildings in the capital, Port-au-Prince, have left a vacuum in leadership and co-ordination.

Elisabeth Byrs, spokeswoman for the United Nations Office for the Co-ordination of Humanitarian Affairs - which oversees the international response to major disasters - has described the situation as "a logistical nightmare".

There is no running water or electricity, communications are down and vital heavy-lifting equipment is still to reach the areas where it is most needed. Food and water supplies are running down and eight of the capital's major hospitals are severely damaged. The Haitian Red Cross said it had run out of body bags.

Shaul Schwarz, a photographer for Time magazine, said increasingly-desperate survivors has set up road blocks made from corpses in an attempt to get aid and rescue workers to stop in their areas. "Thery are starting to block the road with bodies," he told Reuters. "It's getting ugly out there. People are fed up with getting no help."

The organiser of one of the makeshift tented camps that have sprung up around the city, Valery Louis, said: "These people have no water, no food, no medicine. Nobody is helping us."

The country's main prison was among the buildings destroyed, allowing inmates to break free and there are increasing reports of looting and violence. More than 9,000 United Nations peacekeeping troops were already in the country, but they have been overwhelmed by the enormity of the task and have also had to help fellow UN workers trapped in the ruins of their building as well as their own families.

The massive US aid effort is getting into gear, with the nuclear-powered aircraft carrier, the USS Carl Vinson, due to arrive off the coast of Haiti later today to form a "floating airport" for helicopters that can be used to ferry in supplies. An American hospital ship and around five and a half thousand troops are also on their way, but may not arrive before Monday.

The first British team of 42 rescue workers are already on the ground in Port-au-Prince and are due to be joined by a second group of 27 with two sniffer dogs, who are travelling over from Santa Domingo.

The Disasters Emergency Committee is launching its Haiti Appeal tonight. Its chief executive, Brendan Gormley, said the quake had "ripped apart the lives of millions of people in one of the poorest nations of the world."

He added: "It is clear that, after the immediate rescue attempt is completed, we will be left with ongoing humanitarian challenges."