(CNN) -- The mayor of tornado-ravaged Moore, Oklahoma, will push for a law requiring storm shelters or safe rooms in new homes, he told CNN Wednesday.
"We'll try to get it passed as soon as I can," Glenn Lewis said.
The ordinance would apply to single-family and multifamily homes.
At least 24 people, including nine children, were killed in Monday's mammoth tornado, the state medical examiner's office said. Another 324 people were injured, Gov. Mary Fallin said Wednesday.
Lewis said he does not expect the death toll to rise.
But Albert Ashwood, the state's emergency management director, said six people remain unaccounted for.
The twister ripped through 17 miles of central Oklahoma and pummeled 2,400 homes.
Cassandra Jenkins has no idea what happened to her grandparents, more than a day after the twister struck their hometown of Moore.
"All we know is that their home is still left standing. However, they have not been seen or heard from since the storm hit," she said as her daughters clutched photos of their great-grandparents.
"We've tried to locate them at every hospital, every shelter, every Red Cross. Anything we could possibly reach out to, we have."
President Obama will travel to the area Sunday to witness the devastation first-hand, the White House announced.
Young lives remembered
One of the most heartbreaking scenes in Moore is the pile of wreckage where Plaza Towers Elementary School once stood.
Seven of the nine children killed in the storm were inside the school when it collapsed.
The children were in a classroom, Moore Fire Chief Gary Bird told CNN Wednesday. He also said their deaths "had nothing to do with flooding, from what I understand." On Tuesday, Lt. Gov. Todd Lamb told CNN the youngsters had drowned in a school basement.
Local resident Adam Baker told CNN he rushed to the school to help in the aftermath. He found some children who had died in a shallow space.
"The ones that were deceased had bumps, scrapes, and they probably would have made it if they weren't pinned. It looked like most of them just drowned -- all blue and stuff." Pieces of pipe, metal, desks, 2-by-4s, and other debris were on them, he said.
Officials have not yet released official causes of death.
Ja'Nae Hornsby, 9, was one of them.
"There's no other kid like her," Ja'Nae's aunt Angela Hornsby said. "She's the sweetest thing, the bossiest thing, the most fun, always trying to make us laugh."
Ja'Nae's father, Joshua Hornsby, isn't ready to accept that his little girl is gone.
"I'm still hoping for that call to say, 'We've made a mistake,'" he said. "I just pray that's what it is."
Destruction on a colossal scale
Damage assessments Tuesday showed the tornado had winds over 200 mph at times, making it an EF5 -- the strongest category of tornadoes measured, the National Weather Service said.
Lewis said the devastation was so catastrophic that city officials rushed to print new street signs to help guide rescuers and residents through the newly mangled and unfamiliar landscape.
Insurance claims related to damage from Monday's tornado and storm in metropolitan Oklahoma City are likely to top $2 billion, said Kelly Collins, a representative of the Oklahoma Insurance Department.
Craig Fugate, the Federal Emergency Management Agency administrator, told CNN the agency is in "good shape" to support the recovery in Oklahoma and in other disaster zones, such as rebuilding after Hurricane Sandy in New Jersey and New York. "We got full allocation last year with the Sandy supplemental funds. We are looking to continue the response here as well as the previous disasters."
But "if we have another hurricane, we may need more money," he said Wednesday.
About 10,000 customers remained without power on Wednesday, down from 37,000, Governor Fallin said.
Those helping in Moore include police and firefighters from Joplin, Missouri -- a city all too familiar with grief and devastation.
Wednesday marks the second anniversary of the tornado that pulverized Joplin, killing at least 158 people. It was the deadliest single U.S. tornado since federal record-keeping began in 1950.
"We remember the amount of assistance that we received following the tornado two years ago, and we want to help others as they helped us," Joplin City Manager Mark Rohr said.
"We know too well what their community is facing, and we feel an obligation to serve them as they have served us."
'Still can't believe this'
Some residents of Moore ventured back to where their homes once stood, only to find unrecognizable scraps of their lives.
"You just want to break down and cry," Steve Wilkerson said, his voice trembling.
He held a laundry basket that contained the few intact belongings he could find.
"I still can't believe this is happening. You work 20 years, and then it's gone in 15 minutes."
CNN's Sara Weisfeldt, Nick Valenica, Josh Levs, Brian Todd, Mayra Cuevas, Anderson Cooper, Gary Tuchman, Ed Lavandera, Dana Ford, Pamela Brown and George Howell contributed to this report.