Houston - As Hurricane Ike slowed to a tropical depression Sunday after carving a path of destruction through Texas, rescuers were using everything from dump trucks to boats and helicopters to reach stranded residents.

The victims, many of whom had ignored mandatory evacuation orders, were trapped on rooftops or amid debris in unstable houses without electricity or clean water.

In Orange Country, Texas, police were using dump trucks to rescue residents trapped on roofs for nearly 12 hours as the flood waters rose. Up to 200 people, including an 8-week-old baby and an 80-year- old woman, were rescued by Sunday afternoon, emergency officials told CNN.

Thousands of Army and Air Force National Guard troops, along with outlying fire and rescue crews, were hustling into the hardest-hit areas to search for survivors and aid in relief efforts. Homeland Security Secretary Michael Chertoff said more than 50 aircraft were in use to spot people in distress.

"Our first priority right now is lifesaving efforts," Federal Emergency Management Agency chief David Paulison said. "We're working very hard to do the search and rescue operations. They are underway, and there's a lot being done by all the different agencies. We have a large combination of state and federal responses out there right now."

Some trapped residents used their ingenuity and a little bit of luck to get to dry land. Paul and Kathi Norton, who overslept as Ike approached their home in coastal Texas, managed to float out on a suitcase.

Even though their house in Crystal Beach was on 4.5-metre stilts, it couldn't withstand the battering as Ike made landfall. "It took the floor up ... we dove out the door and grabbed the staircase, and we floated off," Kathi told KHOU-TV in Houston. The Nortons were later rescued by a National Guard helicopter.

Post-hurricane rescue efforts also focused on Galveston on the Texas coast after Ike roared inland from the Gulf of Mexico. An estimated 20,000 people refused mandatory orders to evacuate Galveston, which sits on a barrier island, despite warnings from the US National Weather Service, which predicted "certain death" for occupants of especially vulnerable houses.

Ike made landfall early Saturday with winds topping 170 kilometres an hour and a huge storm surge that pushed water up to 2 metres deep into the streets of Galveston and parts of Houston, where 4 million people live 60 kilometres inland.

The diameter of the storm, which at its peak covered much of the upper Gulf of Mexico, was blamed for the unusually high and far- reaching surge of seawater, which affected coastal communities as far off as Louisiana and Mississippi.

By Sunday afternoon Ike weakened to a tropical depression with winds of 25 kilometres per hour and was moving on a north-eastward path through the Midwest.

But it will take Texas several weeks, months even, to recover, officials said Sunday. US President George W Bush said he would visit Texas on Tuesday "to express the federal government's support - sympathy on the one hand and support on the other to - for this recovery effort and rebuilding effort."

Bush issued additional disaster assistance to local governments in 29 Texas counties and declared a major disaster from Ike in parts of neighbouring Louisiana, which is still recovering from Hurricane Gustav on September 2.

The federal government would be providing 1.5 million litres of water and 1 million meals a day to help those who have been displaced, the president announced Sunday.

Before Ike made landfall, an estimated 2.2 million Texans evacuated their homes. But even those who could return Sunday, were likely to remain without electricity for days.

As streets remain flooded, strewn with debris and without lights, and with police concerned about the security of returning residents, the Houston chief of police ordered a 9 pm to 6 am daily curfew for the entire city until next Saturday.

While some lights flickered across Houston on Sunday, officials said it was unlikely that a full service would be restored before a month, and estimated that nearly 5 million people in the region were without power.

At least three US deaths were blamed on Ike, which killed 72 people in Haiti and seven in Cuba as it churned through the Caribbean.

In 1900, up to 8,000 people died in Galveston during and after a hurricane, which remains the deadliest natural disaster in US history. In 2005, Hurricane Katrina killed about 1,800 people in New Orleans and the surrounding Gulf coast.