U.S. and Canadian security officials warned Sunday that violence in Haiti could further hinder a massive relief in the quake-ravaged nation, as frustration and anger about patchy aid began to spread through the shattered capital of Port-au-Prince.

The comments came just as food and water trickled into the city and the global aid mission appeared to lurch into action after several days of bottlenecks.

Recent Developments:

  • Bill Clinton to travel to Haiti Monday
  • Canadian Red Cross reports $22.2 million in donations
  • UN plans to feed 1 million people within two weeks
  • Up to 3.5 million in need of aid

According to Lt. Gen. Ken Keen of the U.S. Southern Command, violence was getting in the way of some relief work, despite the fact that 1,000 U.S. troops are on the ground in Haiti, and another 3,000 are working from ships.

"We are going to have to address the situation of security," Keen said.

"We've had incidents of violence that impede our ability to support the government of Haiti and answer the challenges that this country faces."

About 12,000 U.S. troops will eventually arrive in the country by Monday, bolstering a UN presence of 9,000 peacekeepers and international police.

About 2,000 Canadian troops will also eventually be deployed to the country, to hand out aid and bolster security.

The Canadian Press also reported that an aggressive crowd gathered around the Canadian embassy Sunday.

Canadian police have been also expressed concern about violence, with reports surfacing that roadblocks have been erected in some Port-au-Prince neighbourhoods, further straining aid delivery.

Frustration mounts

Meanwhile, UN Secretary-General Ban Ki-moon arrived in Haiti on Sunday and began to asses the destruction from Tuesday's 7.0 quake.

Ban has said that the disaster is "one of the most serious crises in decades," adding that "the damage, destruction and loss of life are just overwhelming."

While he said workers are doing what they can, he acknowledged "that many people are frustrated and they are losing their patience."

He also and pleaded for patience in hopes of preventing violence and rioting.

Ban stopped at the collapsed U.N. mission headquarters before seeing the plaza in front of the severely damaged National Palace where thousands of needy Haitians were camped hoping for work, food and water.

He cautioned that rescue missions need to be focused to best utilize resources.

"We should not waste even a single item, a dollar," he said.

On Sunday, drumbeats could be heard around the city as Catholic and Protestant worshippers walked through the crumbled capital on their way to mass.

But signs of frustration about the delayed relief effort were everywhere.

"The government is a joke. The UN is a joke," said 71-year-old Jacqueline Thermati, who was laying in a damaged hospice.

Dozens of others nearby appeared to be close to death.

In other areas of the capital, citizens have begun to lash out at looters, who have further hampered the delivery of food, water and medicine.

The Associated Press reported that two suspected thieves could be seen laying on the street in the Delmas neighbourhood of Port-au-Prince, both badly beaten and bound.

Some witnesses said the men were beaten by angry locals; others said police were responsible for the beatings. A few hours later, both men were dead.

Locals said the two were criminals who were among thousands of convicts who escaped from a prison which was badly damaged in the quake.

Incoming supplies

Bill Clinton, the special UN envoy to Haiti, plans to arrive in the country on Monday. Clinton and his agency plan to deliver more aid to the nation.

Meanwhile, as some agencies had complained that back-ups at the airport have hampered the delivery of aid, others said the co-ordination was improving and relief supplies were beginning to flow.

The UN reported Sunday that it had distributed 130,000 meals, but officials acknowledged that much more was needed.

The UN World Food Program plans to feed upwards of 1 million people within two weeks. They hope to reach 2 million within a month.

The Canadian Red Cross has raised more than $22.2 million so far in pledges, with a three-year campaign to raise $105 million.

Ottawa has stated that it will match private donations to registered groups to an amount up to $50 million.

Care Canada has also began the task of handing out 75,000 water purifying tablets in Haiti.

"We're getting more supplies and more people by the hour," said the group's Audree Montpetit.

Meanwhile, World Vision and UNICEF are working to set up special safe zones where children can get food and medicine.

Haiti has a mean age of around 20 years, and about 40 per cent of the population is younger than 19.

Hope amid destruction

Meanwhile, small miracles continue in Haiti while large-scale suffering continues to grip much of the populace.

Onlookers in Port-au-Prince cheered early Sunday as rescuers removed a dehydrated but otherwise uninjured woman from a collapsed luxury hotel.

"She's one tough cookie. She is indestructible," Reinhard Riedl, the woman's husband, told reporters.

Experts say that in general, people can't survive for more than three days when caught in a collapsed building, although a few people have managed to beat the odds.

Stuart Coles, from Plan International, told Â鶹´«Ã½ Channel Sunday that thousands of people have "serious injuries that need rapid treatment."

Coles said many in his group are Haitians who have been working tirelessly since the quake struck.

"People are working from dawn until they drop," he said, adding that looking after children has been the group's priority.

However, the main problem continues to be getting aid out to the survivors of the quake who have no food, water, shelter or medical care.

The quake is estimated to have killed between 50,000 and 100,000 people -- including eight Canadians -- and affected a total of three million Haitians.

About 20,000 bodies have been driven out of town to be burned, the Haitian government said.

The country's main airport has been rammed with aircraft attempting to deliver supplies, leading to some conflicts between national governments over access. Meanwhile, relief workers rushing to the decimated capital have been slowed by clogged roads.

With files from The Associated Press