The supply lines of aid to Haiti are apparently incredibly splintered right now.
The airport at Port-au-Prince has been handed over by the Haitian government to US military control, the UN mission is Haiti is under the control of Brazil however. But while US Military flights are getting prioritised to the airport non-US flights, often carrying aid, are being diverted to the Dominican Republic. This is what has happened to Médecins Sans Frontières and Red Cross supply flights and is leading to tensions with the US over the control of access to the airport and therefore the people who need the aid. The turning away of supply flights is leading to 24 hour delays of these resources getting where they are needed.
When Ban Ki-Moon was in Haiti yesterday he said that the UN were feeding 40,000 people and hoped to raise this to 1m within a fortnight. Problem is that many of that million will be needing such support a whole lot quicker than that. That case is evidenced by the population turning on itself to try and feed itself, and the swift and brutal retribution carried out against looters. Currently the US Military presence has been barracked at the Airport but it needs to be spread out amongst the people to help the 3,000 Haitian police maintain law and order.