"We will rebuild, and we will regain our strength," Fallin said.
In describing the bird's-eye view of the damage, the governor said many houses were "taken away," leaving "just sticks and bricks, basically. It's hard to tell if there was a structure there or not."
From the air, large stretches of town could be seen where every home had been cut to pieces. Some homes were sucked off their concrete slabs. A pond was filled with piles of wood and an overturned trailer.
Also visible were large patches of red earth where the tornado scoured the land down to the soil. Some tree trunks were still standing, but the winds ripped away their leaves, limbs and bark.
In revising its estimate of the storm's power, the National Weather Service said the tornado had winds of at least 200 mph and was on the ground for 40 minutes.
The agency upgraded the tornado from an EF4 on the enhanced Fujita scale based on reports from a damage-assessment team, said spokeswoman Keli Pirtle. Monday's twister was at least a half-mile wide. It was the nation's first EF5 tornado of 2013.
Other search-and-rescue teams concentrated on Plaza Towers Elementary, where the storm ripped off the roof, knocked down walls and destroyed the playground as students and teachers huddled in hallways and bathrooms.
Seven of the nine dead children were killed at the school, but several students were pulled alive from under a collapsed wall and other heaps of mangled debris. Rescue workers passed the survivors down a human chain of parents and neighborhood volunteers. Parents carried children in their arms to a triage center in the parking lot. Some students looked dazed, others terrified.
Neither Plaza Towers nor another school in Oklahoma City that was not as severely damaged had reinforced storm shelters, or safe rooms, said Albert Ashwood is director of the Oklahoma Department of Emergency Management.
More than 100 schools across the state do have safe rooms, he said, explaining that it's up to each jurisdiction to set spending priorities.
Ashwood said a shelter would not necessarily have saved more lives at Plaza Towers.
"When you talk about any kind of safety measures .<\!p>.<\!p>. it's a mitigating measure, it's not an absolute," he told reporters. "There's not a guarantee that everyone will be totally safe."
Officials were still trying to account for a handful of children not found at the school who may have gone home early with their parents, Bird said.
On the streets of Moore, evidence of the storm's fury stretched in every direction: Roofs were torn off houses, exposing metal rods left twisted like pretzels. Cars sat in heaps, crumpled and sprayed with caked-on mud. Insulation and siding was piled up against any walls still standing. Yards were littered with pieces of wood, nails and pieces of electric poles.
President Barack Obama pledged to provide federal help and mourned the death of young children who were killed while "trying to take shelter in the safest place they knew -- their school."
The town of Moore "needs to get everything it needs right away," he said Tuesday.
Moore has been one of the fastest-growing suburbs of Oklahoma City, attracting middle-income families and young couples looking for stable schools and affordable housing. The town's population has grown over the last decade as developers built subdivisions for people who wanted to avoid the urban problems and schools of Oklahoma City but couldn't afford pricier Norman, the college town next door.
Many residents commute to jobs in Oklahoma City or to Tinker Air Force Base, about 20 minutes away.