THE UN warned last night that Haiti was sinking into potentially violent chaos as people grow frustrated at the slow pace of aid getting through.
Most victims are still living outside in squalid tents of sheets and sticks and aid officials acknowledge they have not yet got food to most of those in need.
Mobs have stolen food and looted goods from their neighbours in the camps, prompting many to band together or stay awake at night to prevent raids.
About 20 armed men blockaded a street and attacked a convoy carrying food from the airport in Jeremie. UN and Haitian officers fired warning gunshots and the men fled.
Haitian police have increased their own patrols and are accompanying UN police guarding aid distribution.
"The overall security situation across the country remains stable but potentially volatile," the UN mission said.
In Jacmel, also a southern city, 33 prisoners on the run were caught , the UN said after mass escapes when prisons collapsed.
While Haitians are still mourning friends and relatives, many still unburied, anger at the government's sluggish response to the quake is feeding political resentment.
Hundreds gathered yesterday at a gravel pit in Titanyen where countless earthquake victims had been dumped, turning a remembrance ceremony for the dead into one of the first organised political rallies since the disaster.
Many denounced President Rene Preval and called for the return of ousted president Jean-Bertrand Aristide.
Critics were already blaming Mr Preval for rising unemployment, corruption and greed before the earthquake struck.
He has rarely been seen in public since, leaving his ministers to defend his performance and discontent with him appears to be growing, three weeks after the disaster.
Mr Aristide also faced criticism during his presidency. The former slum priest had a huge grassroots following among Haiti's poor but was overthrown in 2004 as corruption and drug trafficking grew rampant.
Haiti's government also has had to deal with the 10 Americans who tried to take a busload of undocumented Haitian children out of the country. The Idaho-based church group was being held without charges at a police station yesterday. US embassy officials would not say if a US court process was possible.
Meanwhile Spain announced yesterday that it would perform DNA tests on children in Haiti to try to reunite them with their parents and protect them from traffickers.
Secretary of State for International Co-operation Soraya Rodriguez said Spain would send genetic testing kits and technicians to the quake-ravaged nation in the coming days.
The initial goal of the programme is to take saliva or blood samples from up to 6,000 Haitian children and adults and create a DNA database for Haitian authorities to use in reuniting families.
The genetic identification programme was developed by the University of Granada in southern Spain.
There are now an estimated 400,000 unaccompanied children in Haiti.