|The Haitian Red Cross says the earthquake killed between 45,000 and 50,000 [AFP/UN/Mintusah]
Aid agencies are struggling to reach the up to three million of people affected by an earthquake that has devastated Haiti, levelling buildings and burying thousands of people in the rubble.
At least 300,000 people were estimated to be homeless in Port-au-Prince on Friday, more than 48 hours after one in 10 homes in the capital collapsed, the United Nations said.
Many more people were believed to be sleeping on the streets fearing aftershocks will cause more buildings to fall.
Rescue and aid efforts have been been hampered by blocked roads, severed communications lines and the difficulties faced by relief agencies that have lost personnel and seen their office destroyed.
The capital's port was too badly damaged to handle cargo and supply planes arrived at the airport faster than ground crews could unload them, prompting aviation authorities to restrict non-military flights for fear jets would run out of fuel while waiting to land.
Alejandro Lopez-Chicheri, senior spokesman for the World Food Programme for Latin America, Central America and the Caribbean, said that Haiti was "completely on the ground".
"The roads, many of them are still to be opened, and on the ones that are open there are still people concentrated on the sides of the roads," he told Al Jazeera from Port-au-Prince.
"This is a logistical challenge. Before the earthquake struck we were already assisting one million people here, we are considering it will be at least double that after this earthquake."
There was growing frustration among the thousands of people living out on the streets of Port-au-Prince who had received little or no help.
"A lot of people have simply grown tired of waiting for those emergency workers to get to them," Al Jazeera's Sebastian Walker said.
Al Jazeera's Mike Kirsch reports on Haiti quake survivors who have been left homeless
"Thousands of people are streaming out of the city towards the provinces to try to find supplies of food and water, supplies that are running out in the city."
David Wimhurst, spokesman for the Brazilian-commanded UN peacekeeping force, said: "Unfortunately, they're slowly getting more angry and impatient.
"I fear, we are all aware that the situation is getting more tense as the poorest people who need so much, are waiting for deliveries. I think tempers might be frayed."
Shaul Schwarz, a photographer for Time magazine, said he saw at least two roadblocks, formed with the bodies of earthquake victims and rocks, built by Haitians desperate for food and water.
"They are starting to block the roads with bodies. It's getting ugly out there. People are fed up with getting no help," he told the Reuters news agency.
The Haitian Red Cross said it believed 45,000 to 50,000 people had died in the quake, while Rene Preval, Haiti's president, said 7,000 dead had already been buried in a mass grave.
Rescue workers were able to free a few people who had been trapped under the rubble for days as others dealt with the hundreds of bodies that were lying in the streets of the city.
Jamieson Davies, international programmes director for the Caritas relief organisation, said that the situation was "extremely difficult" as aid workers were suffering the same hardships as the Port-au-Prince residents.
"Even the aid workers themselves are sleeping in cars or in tents on the streets," she told Al Jazeera from Sydney, Australia.
"But luckily they have direct access to stocks of relief that were already placed around the country.
"Right now our staff are delivering first aid to survivors, as well as blankets, tents, things that they need to spend the night safely on the streets."
The UN World Food Programme said that it was working to get together enough supplies to feed two million Haitians for a month.
"We are hoping that people will come forward and give and we are particularly urging meals ready-to-eat and the high-energy biscuits, 80 to 90 tonnes of which has already been flown in from El Salvador," Caroline Hurford, a London-based spokesperson for the agency, told Al Jazeera.
"This is what people really need when they have lost their houses, they have lost their ability to prepare food, and they are desperately hungry."
UNFP said that food shops across Port-au-Prince had been "cleared out" since the quake and desperate survivors stole some of the stockpile of food aid from its warehouse.
Al Jazeera and agencies