Map: Flooded New Orleans

The mayor of New Orleans said 80% of the city was flooded

As a result of Hurricane Katrina the levees or walls keeping water out of the New Orleans have been breached, and emergency teams are using helicopters to drop 1,350kg (3,000lb) sandbags and concrete barriers into the gaps

New Orleans mayor Ray Nagin said up to 80% of the city was submerged, in some cases by waters 6m (20ft) deep. He warned water levels could still rise.

The US Army Corps of Engineers said it could take a month to clear the flood waters, and the government's disaster relief agency has urged evacuees not to try to get back to their homes.