Hurricane Isaac: Obama visits storm-hit Louisiana
US President Barack Obama has visited Louisiana as the Gulf Coast continues to grapple with flooding and power cuts in the wake of Hurricane Isaac.
He spoke of "enormous devastation", praised those who saved lives and hailed disaster relief co-ordination by state and federal authorities.
Thousands of evacuees are in shelters, or with friends and relatives.
Isaac killed seven people - five in New Orleans and two in Mississippi - seven years after Hurricane Katrina.
Mr Obama was met in New Orleans by Louisiana Governor Bobby Jindal and city Mayor Mitch Landrieu, before heading off to visit storm damage in St John the Baptist Parish.
"Obviously right now we are still in recovery mode," the president said after his tour, before adding: "The good news is that the army corps levees... worked very well."
He pledged that the US federal government would work to speed up "any decisions that need to be made" to ensure the entire region was protected by flood defences for future storms.
His visit came after Republican opponent Mitt Romney toured storm damage in Louisiana on Friday.
Early on Monday, utilities said that nearly 240,000 people had no electricity in Louisiana, although that figure was lowered significantly to about 100,000 as the day went on.
More than 11,000 were without power in Mississippi. About 5,000 were without power in Arkansas.
"My family is split up," Angela Serpas, resident of hard-hit Plaquemines Parish, told the Associated Press news agency. "This is the second time we've lost our home. We lost it in Katrina."
Residents who were evacuated from Plaquemines Parish, a vulnerable stretch of land extending to the Gulf of Mexico, will be allowed to return temporarily under police escort on Monday.
Over 3,500 people were still in shelters on Sunday, according to the office of Governor Bobby Jindal.
Thousands of people were forced out of their homes in that area after storm surge drove water over the banks of Lake Pontchartrain.
Crews are also still clearing debris left by Isaac, mostly downed trees and power lines. So far, state workers in Louisiana have cleared 130 miles (210km) of roads.
In St Tammany Parish, Louisiana, which lies to the north of New Orleans, authorities were dealing with threats from the swollen Pearl River and a lock under pressure in a canal.
The lock was opened to release water and a mandatory evacuation notice was lifted, but officials encouraged residents to stay away from the area.
In the town of LaFitte, rescue teams intentionally breached a levee on Sunday to ease flooding in the area, the Times-Picayune newspaper reported.
Forecasters are expecting the Pearl River to crest on Monday at 19.5ft (5.9m), potentially putting thousands of homes at risk of flooding.
Meanwhile, in Mississippi, the swollen Wolf River is due to crest on Tuesday, weather forecasters said.
In the wake of Hurricane Katrina, which killed almost 1,800 people, the federal government spent $14.5bn (£9.1bn) rebuilding the city's flood defences. Hurricane Isaac marked the first real test of the revamped system.
Although Hurricane Isaac did not have the same force as Katrina, the storm moved slowly and dumped large volumes of rain on Louisiana and Mississippi.
Many of the areas hardest hit by the hurricane were not protected by the New Orleans flood barriers.
At the height of the storm, about 850,000 people were reported to have lost power in Louisiana, Mississippi, Alabama, Texas and Arkansas.