Law and order began to break down in Haiti yesterday as "constant" gunshots were heard across the capital and shops were looted.
Aid groups in Port-au-Prince said the relief effort could be hampered by the deteriorating security situation as criminals and desperate locals fought for the scarce resources.
More than 3,500 US troops are due to arrive in the country by the end of the week to bolster around 3,000 police and international peacekeepers who were said to have been deployed to secure the airport, port and main buildings.
But charity workers said they had seen little evidence of the security measures and warned of widespread looting and fights breaking out over dwindling water supplies.
Inmates escaped from the damaged main prison in Port au Prince on Tuesday when it collapsed in the earthquake.
Thieves were blamed for starting at least one mass panic in the city's central square during the night, spreading rumours that a tidal wave was coming so they could steal the belongings left behind by hundreds of fleeing people.
Thieves also descended on a half-collapsed supermarket in the Delmas area of Port-au-Prince, carrying out electronics and bags of rice. Others siphoned gasoline from a wrecked tanker.
With law enforcement stretched thin even before the earthquake and the UN's 9,000 peacekeepers distracted by the collapse of their headquarters and the loss of up to 100 staff, the country is ill-equipped to deal with major unrest.
Matt Marek, Haiti country representative of the American Red Cross, said: "There has been widespread looting of collapsed buildings since the earthquake hit. There is no other way to get provisions. Even if you have money, those resources are going to be exhausted in a few days." (© Daily Telegraph, London)