Some residents of the southern state of Louisiana are being allowed back home sooner than expected after Hurricane Katrina struck the coast of the Gulf of Mexico last month. People returning home still face problems.

Residents of Gretna and two other cities near New Orleans are being allowed to return to their homes, now that electrical service to much of the area has been restored. A nighttime curfew will remain in effect.

Tests of the floodwaters in New Orleans have found high levels of bacteria and toxic chemicals. Officials are warning people to avoid contact with standing water. That could affect plans to allow some residents to return to the city next week.

Federal prosecutors said Wednesday they will aggressively prosecute any hurricane-related fraud. In Baton Rouge, Louisiana, United States Attorney Jim Letten said that fraud could take many forms.

"Any type of fraudulent activity which may be aimed at either illegally and fraudulently obtaining charitable funds or government funds or any other type of relief that's destined for the victims of Katrina or rebuilding efforts for that matter," said Mr. Letten.

In New Orleans, the Louis Armstrong International Airport has reopened for scheduled flights. Airport spokesman Michelle Duffourc says United States Transportation Secretary Norman Mineta announced emergency relief funds as he toured the facility.

"We actually just had a visit from Secretary Mineta. He has come in and given a grant for $15.2 million to start rebuilding and repairing of the airport. We're still looking for a lot more, but at least it's a fresh start," she said.

President Bush is scheduled to speak to the nation Thursday night from Louisiana on the relief mission. On Tuesday the president said he assumes "full responsibility" for federal government failures in responding to Hurricane Katrina. 

In the U.S. Congress, lawmakers are still debating on how to form an investigation commission to look at the federal failures. But the Republican-led Senate rejected Wednesday Democrat Senator Hillary Clinton's call for an independent, bipartisan commission to investigate why the federal government did not respond to the disaster sooner.

In Atlanta, Georgia, a group of church leaders has announced plans to focus on racial and economic disparities that some African-Americans feel contributed to problems in providing assistance after Hurricane Katrina struck the Gulf coast last month.