"We're now facing yet another big storm," Bush said at a Federal Emergency Management Agency facility. "And the folks here ... are working so hard to help the folks on the ground prepare for the storm."

Bush had planned to visit San Antonio, Texas, to inspect "prepositioned assets" for hurricane victims but he scrubbed the Texas leg of his trip just minutes before his scheduled departure.

White House spokesman Scott McClellan said the Texas leg was dropped because search and rescue teams Bush had planned to meet with in San Antonio were going to move to a location nearer to Rita's expected landfall.

"We didn't want to slow that down," McClellan said.

In Colorado, Bush is to tour the military's Northern Command headquarters to see how it was preparing for the storm with state and local authorities.

"Our job is to assist, prepare for and assist the state and local people to save lives and to help these people get back on their feet," Bush said.

Asked if he would be heading to the hurricane strike zone now, Bush said "NorthCom is the main entity that interfaces, that uses federal assets, federal troops to act with federal and state government.

"It's an important relationship and I need to know how it works better. We will make sure that my entourage does not get in the way of people doing their job, which will be search and rescue immediately."

Rita threatened Texas and Louisiana three weeks after Hurricane Katrina crushed the Gulf Coast August 29, killing more than 1,000 people.

The White House said earlier that Bush had been saddened by reports that a bus carrying elderly evacuees fleeing Hurricane Rita exploded into flames, killing at least 20 people.

"He was briefed on that this morning in his hurricane briefing. Our thoughts and prayers are with the families of the victims. We were all saddened to learn of the news," White House spokesman Scott McClellan told reporters.

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