Two babies are among the 24 people killed by a tornado that tore through this US community, officials said Wednesday, as residents began the daunting task of rebuilding their lives.

Ten children -- including a pair of infants four and seven months old -- perished in Monday's fierce twister that steamrolled entire neighborhoods and two schools in the Oklahoma City suburb of Moore.

"Our hearts go out to all the people affected by this tragedy," Amy Elliott of the state medical examiner's office said in an email detailing the revised breakdown of the official death toll. Previously, authorities had put the number of child fatalities at nine.

President Barack Obama will visit the ravaged region on Sunday to meet with victims and get a firsthand look at the stunning, widespread damage of an area that was previously razed by a still deadlier tornado in May 1999.

The preliminary causes of death for the two dozen casualties included blunt force traumas, as well as asphyxiation, according to the Oklahoma Medical Examiner's Office, which also released some of their names. Both babies died of head trauma.

Some 237 people were injured by the hurricane-strength storm, Oklahoma Department of Emergency Management spokesman Andy Oden told AFP.

It was not immediately clear if anyone remains unaccounted for, with Governor Mary Fallin urging everyone affected to come forward.

"We need to know where you're at. We need to know if you need assistance," she said.

During a visit to tour the damage, Homeland Security Secretary Janet Napolitano pledged government support for those struggling to piece their lives back together.

"At some point the cameras will leave, the national ones will leave first, then the local ones," she said. "But on behalf of President Obama and on behalf of (the Federal Emergency Management Agency), we will be here to stay until this recovery is complete."

Moore Mayor Glenn Lewis vowed to propose an ordinance in the coming days at the local city council to require the construction of tornado shelters in new homes, and expressed confidence he would get the necessary votes for the measure.

Fallin, the governor, agreed on CNN that it was "certainly wise" to install safe rooms, particularly in schools.

No state or local law in Oklahoma, the "bullseye" of Tornado Alley, mandates the installation of residential storm shelters -- and homeowners who do opt for them have to shell out upwards of $4,000 for the most basic option.

As a result, few people who live in "Tornado Alley" bother with the trouble and expense of a proper shelter from the storms.

For residents whose lives were turned upside down, relief about having survived turned to heartbreak as the extent of the disaster slowly sunk in.

Curtis Carver, a 20-year veteran of the US Marine Corps who served two years in Iraq, described his hometown as a "war zone" as he waited at a police checkpoint for permission to recover keepsakes from the ruins of his house.

"It was my home, my kids' home," said the 38-year-old father of two, both of whom escaped harm. Carver was not allowed past because his house was in an area still deemed too dangerous.

"Now it's gone. There's nothing left. It's a pile of sticks... and they're keeping me away," he said.

The tornado was the strongest possible category, EF5, packing winds of more than 200 miles (320 kilometers) per hour, Kelly Pirtle of the National Weather Service's Severe Storms Laboratory in nearby Norman told AFP.

The epic twister, two miles across, flattened block after block of homes as it struck, hurling cars through the air, downing power lines and setting off localized fires in a 45-minute rampage.

The epicenter of the tragedy was the Plaza Towers Elementary School, where frightened teachers and students huddled in hallways and bathrooms as the twister barreled through, and where some of the children died.