Hurricane Ike evacuees Wilbur Ball, left, Thelma Stewart and Robert Greenleaf pass the time at a San Antonio hurricane shelter after being evacuated Monday from their homes in Gilchrist, on Texas's Bolivar Peninsula. (Darren Abate/Associated Press)

Rescuers went door-to-door hunting for Hurricane Ike survivors in Texas on Monday as authorities confirmed the storm was responsible for at least 33 deaths in nine states.

Authorities said they are assessing the damage from the U.S. Gulf Coast to Ohio after the storm made landfall early Saturday in the Texas city of Galveston and marched north.

Millions of Americans were still without power Monday, while thousands were left homeless and forced to take refuge in temporary shelters. Others were coping with severe flooding and cleaning up mountains of debris.

City workers in Houston clean up debris Monday left by fallen trees in the aftermath of Hurricane Ike. (Marcio Jose Sanchez/Associated Press)

Houston, strewn with glass after the hurricane damaged many skyscrapers, was placed under a weeklong curfew to ensure public safety, according to Houston police Chief Harold Hurtt. The curfew from 9 p.m. until 6 a.m. will not be lifted until Saturday morning.

In areas of Texas hard hit by the hurricane, including Orange, Bridge City and Galveston, officials continued to search houses for people who defied evacuation orders.

Rescuers were flown into the barrier island of Bolivar Peninsula, a resort community of 30,000 just east of Galveston, where homes were completely washed away. In other areas, entire subdivisions were submerged and rescuers feared they'd find more victims than survivors.

"They had a lot of devastation over there," rescue leader Chuck Jones said. "It took a direct hit."

The search-and-rescue operation involving 1,500 workers is said to be the largest in Texas history.

'Do not come back to Galveston': mayor

Thousands of Texas residents, meanwhile, were in crowded shelters Monday after their homes were damaged or destroyed in the hurricane. Officials said they could be there indefinitely. By Sunday afternoon, more than 2,000 had been pulled from their swamped homes and taken to shelters. Many of those rescued had decided not to follow evacuation orders.

Those who were rescued were put on buses without knowing where they were going or when they could return to their homes.

Other residents were able to remain in their homes, but were left without power or supplies. Long lines formed as people waited for handouts of food and water, or tried to buy gas at stations that were quickly running out of fuel.

Some areas were so damaged that officials were urging residents who had fled not to return to their homes.

"We want our citizens to stay where they are," Galveston Mayor Lyda Ann Thomas said. "Do not come back to Galveston. You cannot live here at this time."

7 dead in Texas, 7 in Louisiana, 6 in Indiana

Kathi and Paul Norton stayed inside their house in Crystal Beach, Texas, until it was swept away. Their flag pole prevented the house from collapsing on top of them while they tried to escape, holding on to a staircase.

"You never know what a hurricane is like until you ride it on a staircase," said Kathi Norton, 47, from a shelter on a former air force base in San Antonio.

The dead included seven in Texas; seven in Indiana; six in Louisiana; two in Tennessee; four in Ohio; three in Missouri; two in Illinois; one in Arkansas and one in Kentucky.

Ike killed more than 80 people in the Caribbean before it hit the U.S.

The storm dumped upwards of 200 millimetres of rain on parts of Indiana, Illinois and Missouri on the weekend, while spawning a tornado in Arkansas that damaged several buildings and delivering hurricane-force winds to Ohio that temporarily shut down Cincinnati's main airport.

Missouri had widespread flooding as the Mississippi River rose to high levels in St. Louis.

"We've got flash flooding all over the place," National Weather Service hydrologist Mark Fuchs said of Missouri.

Oil production damaged

U.S. President George W. Bush, who will visit Texas on Tuesday, warned Monday that people will feel a "pinch" at the pump because of Hurricane Ike's disruption of energy production.

Ike, which was downgraded to a tropical storm after it moved inland, destroyed at least 10 petroleum production platforms in the Gulf of Mexico. There are more than 700 platforms in the Gulf.

As many as 14 Texas refineries are shut because of Ike, representing more than 20 per cent of U.S. refining capacity. The plants escaped major damage but it's not clear how long they will be out of operation.

The damage and shutdowns did little to boost oil and gas prices, however, as the petroleum installations were spared a potentially much worse fate.

Oil prices closed below US$100 a barrel for the first time in six months Monday, tumbling more than $5 as fears over the stability of major U.S. financial institutions rattled global markets.

Meanwhile, authorities said Monday they are investigating claims that close to 300 senior citizens were left by their caretakers at a public housing complex in Houston during the hurricane.

What's left of the storm blew through parts of southern Ontario early Monday, bringing wind and rain. Later Monday, it brought rain and wind to Quebec. The remnants of the storm are headed to New Brunswick and P.E.I.

With files from the Associated Press