A hurricane-damaged neighborhood is seen in New Orleans where flood waters are starting to recede

The head of the U.S. government's hurricane relief effort says it is too soon for residents of New Orleans to return to their storm-ravaged city.

On the Fox News Sunday  program, Coast Guard Vice Admiral Thad Allen urged New Orleans' mayor to "slow down" a plan for city residents to start coming back this week.

In that interview and others with U.S. television networks Sunday, the admiral said officials are still concerned about polluted floodwater, lack of clean drinking water and weakened levees.

Business owners were allowed to return to some parts of New Orleans on Saturday to begin assessing damage and cleaning up.

The number of confirmed deaths from Hurricane Katrina has climbed to nearly 900, with the majority, 646, in the state of Louisiana.

Some information for this story provided by Reuters.