Hurricane Rita quickly intensified into a monster Category 5 storm Wednesday, churning in the Gulf of Mexico with winds of up to 165 mph toward the Texas coast after slapping the Florida Keys.

In an update to an earlier advisory, the National Hurricane Center said this afternoon that reconnaissance aircraft showed Rita has reached the strongest hurricane category, with sustained winds of 165 mph. A Category 5 hurricane has winds over 155 mph.

This morning, Rita's winds were clocked at 140 mph, making it a Category 4 hurricane.

Mandatory evacuations were underway in coastal Galveston, Tex., flood-ravaged New Orleans and parts of Houston. Although the hurricane was veering away from New Orleans, it still forced the evacuation of 7,000 of Louisiana's Katrina evacuees from Texas. And officials in New Orleans warned that as little as three inches of rain could swamp the city's damaged levees, according to the Associated Press.

In Washington, President Bush declared states of emergency in Texas and Louisiana as Rita approached.

The acting director of the Federal Emergency Management Agency, meanwhile, outlined a massive effort to pour military equipment and provisions into Texas ahead of the hurricane's landfall.

R. David Paulison said FEMA has asked the Defense Department for six heavy-lift helicopters, a 2,500-bed hospital system, a food kitchen to serve at least 500,000 meals and temporary bridging equipment for roads washed out by flooding. The helicopters will assist an urban search and rescue effort and help move supplies where they are needed, he said.

In addition, FEMA is working with the Department of Transportation to mobilize buses to evacuate people and is putting in place "a large number of ambulances . . . in case we have injuries there," Paulison said. About 400 disaster medical personnel are already in Texas, along with dozens of truckloads of food and water, he said.

"We are comfortable that Texas is going to be ready for this storm," said Paulison, who took office after Michael D. Brown resigned as FEMA director under heavy criticism for his performance during Hurricane Katrina. "It's not going to be fun."

Rita is "a huge storm," Paulison added "It covers most of the Gulf. We want to make sure we're ready. I'd rather pre-deploy more assets than we need than not have enough."

President Bush used a speech to the Republican Jewish Coalition to urge people in the hurricane's path to comply with the evacuation orders.

"We hope and pray that Hurricane Rita will not be a devastating storm but we got to be ready for the worst," Bush said in his speech to the Jewish group. "I urge the citizens to listen carefully to the instructions provided by state and local authorities and follow them."

Earlier in the day, Homeland Security Secretary Michael Chertoff used various television appearances to also urge residents to quickly leave.

"The lesson is that when the storm hits, the best place to be is to be out of the path of the storm," he told ABC's "Good Morning America." "There's plenty of [advance] notice about Rita."

Gov. Rick Perry (R) of Texas said the first impact from the storm will probably be felt in Texas Thursday morning.

"If you're not out by then, you have problems," Perry said on CNN.

The mayor of Port Lavaca, Tex., located roughly in the middle of the state's 275-mile Gulf Coast and in the projected path of Hurricane Rita, said the town is essentially shutting down in accordance with a mandatory evacuation order.

Allen Tharling told MSNBC that Port Lavaca's hospital and schools were being closed, all major plants were shutting down and all municipal employees except essential personnel were leaving.

"City hall is boarded up," he said.

In New Orleans, a fifth of which is still covered by floodwaters more than three weeks after the onslaught of Hurricane Katrina, Mayor C. Ray Nagin said evacuees are being bused out of the city even as work continues to rescue people and recover the bodies of those who perished in the earlier disaster.

Nagin said a 70-year-old man was rescued from a home Tuesday, five days after the death of his wife. "We are continuing to recover bodies," he said, with recovery teams carrying out detailed searches of homes and attics.

Rita's power grew quickly overnight Tuesday and early Wednesday. At 8 a.m. EDT, Wednesday, the National Hurricane Center upgraded it from a Category 3 to a Category 4. The upgrade came only six hours after it was upgraded from a Category 2 hurricane.

Katrina was a Category 4 hurricane when it slammed into the Gulf Coast Aug. 29, causing devastating damage along the Mississippi, Louisiana and Alabama coastlines.

Rita's sudden burst of power after it passed 50 miles south of Key West, and the possibility that its track could change, sent ripples of anxiety across hundreds of miles of the Gulf Coast, much of it still in the early stages of recovery from Katrina three weeks ago.

Rita is expected to make landfall late Friday or early Saturday anywhere between Corpus Christi, Tex., and Galveston, Tex., the scene of the country's worst hurricane disaster in 1900, when at least 8,000 people died.

"Homes and business can be rebuilt," said Texas Gov. Perry. "Lives cannot. If you're on the coast between Beaumont and Corpus Christi, now's the time to leave." Beaumont is close to the border with Louisiana in the east of the state and Corpus Christi is north of the Mexican border to the southwest.

The National Hurricane Center said Rita was moving west at about 13 mph and that its westward motion was expected to continue for the next 24 hours. Hurricane force winds extended outward up to 70 miles from the eye of the storm, the Hurricane Center said. Meteorologists said the hurricane had developed both a significant eye and eyewall.

At 5 p.m. EDT, the eye of the hurricane was about 600 miles east-southeast of Galveston.

Houston Mayor Bill White called Wednesday for a voluntary evacuation of low-lying, flood-prone parts of the greater Houston area as well as of people living in mobile homes. He said the evacuation order would become mandatory by 6 a.m. Thursday. Houston is just miles from the mouth of Galveston Bay, and if Rita makes landfall where expected, there could be significant flooding inland when the anticipated storm surge rushes through Galveston Bay and along the Houston Ship Channel, officials warned.

Speaking at a news conference, White asked Houston area schools to close Thursday and Friday and area employers to allow all but essential employees to stay home both days.

"Hurricane Rita on its present course poses a risk to Houston and the whole Houston region," White told reporters.

White said there would not be enough government vehicles available to transport everyone who needs evacuating. He asked citizens to lend a hand to those who need help evacuating. The evacuation order could mean that as many as 1 million people may attempt to leave the area.

Crude oil prices surged more than $1 a barrel on concerns that Rita could smash into key oil facilities in Texas and the Gulf of Mexico. Texas is the heart of U.S. oil production and accounts for 25 percent of the nation's total oil output.

Perry activated 5,000 members of the Texas National Guard. Military leaders prepared to rush the USS Iwo Jima, which has served as a floating command post in New Orleans, and several other naval vessels out to sea to better ride out the storm. Emergency workers began plans to open shelters in central Texas.

The scramble to prepare for Rita's next landfall swung into motion even before the storm toppled trees and electrical lines with 90-mph gusts in Key West. But there were no reports of injuries, only isolated flooding. The damage was far less than feared from a storm so fearsome that nearly half of Key West's residents evacuated -- far more than the usual 25 percent on an island famous for its nonchalance in the face of hurricane threats.

"We are very fortunate," Key West Mayor Jimmy Weekley said.

Key West's apparent good fortune, however, did little to ease others' anxiety as the storm grew more powerful. In the Gentilly neighborhood of New Orleans, where neck-high floodwaters from Hurricane Katrina have now receded, the National Guard Tuesday was warning a handful of homeowners who had sneaked into the city to check on their houses that it was time to get out again.

"We are not forcing them, but we will do anything to convince them to get out of here," said Sgt. Timothy Eagle of the Oregon National Guard, who cruised the neighborhood in a Humvee. "We don't want to come back for the body."

Perhaps the worst off, at least psychologically, are the thousands of Katrina evacuees in Texas who are now being "re-traumatized" by a second evacuation.

"You can imagine what's going on in people's minds who lost virtually everything," said Howard B. Smith, associate dean of the College of Education and Counseling at South Dakota State University and coordinator of Red Cross mental health services.

A few evacuees Tuesday began boarding planes bound for Fort Chaffee in Arkansas, a state that will accept 4,000 displaced residents, while an additional 3,000 will be going to Tennessee. One thousand may be going to Nebraska. But some evacuees were unwilling to be uprooted again.

Perry urged residents to fill their vehicles with gasoline, gather personal and financial records, stock up on a three-month supply of needed medications and emergency provisions such as flashlights, water and nonperishable food; and find places to stay inland.

Advance work in Louisiana, where levees are still being repaired and 40 percent of the pumps in New Orleans still do not work, included the staging of 500 buses in case the storm edged toward the city, addressing a lack of transportation that left the city with no choice but to house tens of thousands of people in squalor at the Louisiana Superdome and the convention center in the days after Katrina.

Roig-Franzia reported from New Orleans. Coates reported from Key West. Deane reported from Washington.