Desperately needed aid is still not reaching large swathes of the population [Reuters]

Tensions are rising on the streets of Haiti as the bulk of earthquake survivors continue to go without food, medicine or proper shelter.

Aid organisations continued to struggle to reach them with supplies on Sunday, six nights after the devastating earthquake that killed tens of thousands of people and left hundreds of thousands homeless.

A bottleneck at the capital's small airport – the main entry point for the massive assistance pledged by world leaders following the disaster – means little help has reached the many people waiting for help in makeshift camps on streets strewn with debris and decomposing bodies.

Airport bottleneck

Some aid agencies have complained about a lack of co-ordination at the Port-au-Prince airport, where the US military has taken over operations.

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Medecins Sans Frontieres, or Doctors Without Borders, (MSF) said an aircraft carrying a mobile hospital was denied permission to land at the airport on Saturday and diverted to neighbouring Dominican Republic, where it would take a further 24 hours to deliver supplies by road.

"Priority must be given immediately to planes carrying lifesaving equipment and medical personnel," MSF said in a statement.

Al Jazeera's Teresa Bo, reporting from Port-au-Prince, said quake survivors in the capital were growing increasingly frustrated over what appeared to be the mismanagement or miscommunication that was holding up the aid.

In the absence of large scale foreign help, Haitians were trying to help each other, our correspondent said, with some turning homes into hospitals to treat the wounded and others giving away food, but food supplies and other resources were running out.

People could see helicopters flying overhead, US military vehicles in the city and aeroplanes arriving at the airport with supplies, so it was difficult to understand why little aid appeared to be reaching the people, she said.

Meanwhile the European Union pledged over $575m in emergency and long-term aid, the bloc said on Monday.

The union is also moving towards sending 150 people to assist the police force and help beef up security, as tensions in the Caribbean nation rise.

US defends position

The US military said on Sunday that it was doing its best to get as many aircraft as possible into Port-au-Prince.

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The airport's control tower was knocked out by the quake and US military air controllers were operating from a radio post on the airfield grass, he said.

"What we set up here would be similar to running a major airport ... without any communications, electricity or computers," Colonel Buck Elton, the US commander at the airport, told reporters by telephone.

He said there had been 600 take-offs and landings since his crew took over operations at the one-runway airport's traffic on Wednesday, and 50 flights had been diverted.

But the flow of air traffic was improving, he said, with only three of 67 incoming flights being rerouted on Saturday, and only two flights diverted on Sunday.

'Efficiency increased'

Speaking to Al Jazeera, PJ Crowley, a spokesman for the US state department, defended the US handling of Haiti's airport and international aid.

He said changes in airport procedures "to increase efficiency and effectiveness", as well as "a technical reason", were possible reasons why some aeroplanes were not allowed to land.

Pointing out that the US military had, by adding to the infrastructure of the airport, increased flights from 20 a day to 60 a day, he said whatever limited infrastructure Haiti had before the quake was devastated by the quake and it had taken time to "maximise the flow of everything that Haiti needs".

On claims that military aeroplanes with troops were being allowed to land while those carrying aid supplies were not, he said that was "absolutely not true".

"They are bringing in aid, communications gear for the Haitian government so they can begin to operate and function once again," he said.

Not only food, water, healthcare, he said, but also "the kinds of gear that allows us to save lives, to bring in capacity so that they can establish an effective network to distribute food among the three million people in the city".

Signs of progress

There were some signs of progress on Sunday as international medical teams took over damaged hospitals and clinics where injured and sick people had lain untreated for days.

Aid trucks set out from the airport but were soon blocked by clogged streets [AFP]
A few street markets had begun selling vegetables and charcoal in the capital and US officials said international search teams had rescued at least 61 people alive so far.

Hundreds of trucks carrying aid and guarded by armed UN patrols streamed from the airport and UN headquarters out into the city on Sunday but they were soon obstructed on streets clogged with people, debris and vans carrying coffins and bodies.

There were also scrums for food and water as UN trucks distributed food packets and US military helicopters dropped boxes of water bottles and rations.

Ban Ki-moon, the UN secretary general, who visited Port-au-Prince on Sunday, said the situation in the country was "one of the worst humanitarian crises in decades".

Amid shouts of "where is the food? Where is the help?" from survivors and asked if he feared riots over the delays in aid, Ban appealed to the Haitian people "to be more patient".

Haitian government officials say 70,000 bodies have already been buried in mass graves and estimate the total death toll to be between 100,000 and 200,000.

Source: Al Jazeera and agencies