Gun violence has disrupted the relief effort in New Orleans, as it does in refugee camps and war zones in other countries. The presence of armed civilians is a problem for aid workers throughout the world, according to Cate Buchanan from the Centre for Humanitarian Dialogue.

Medical evacuations from the overcrowded Superdome stadium in hurricane-struck New Orleans had to be halted on 1 September when a shot was fired at a rescue helicopter. There have been continuing reports of armed violence disrupting the relief effort.

Buchanan is the author of 'No Relief', a recent study showing that gun proliferation severely affects the ability of humanitarian aid workers to deliver assistance to communities in need.

Armed threats prevented 21% of aid workers reaching more than a quarter of the people they were supposed to help, according to the research, which surveyed development and humanitarian personnel in 96 countries.

The report found that the most significant threat facing aid workers was civilians armed with guns, especially handguns.

The New Orleans police have said that after a week of near anarchy in the city, no civilians will be allowed to carry guns of any kind. In neighbouring areas, an increased fear of violence from people displaced from hurricane-affected regions has led to greater gun sales, according to the Houston Chronicle newspaper.