Darkness fell on an Oklahoma City suburb gripped by a frantic search for pupils, teachers and staff members in an elementary school flattened by a tornado.

Parents raced to Plaza Towers Elementary in Moore, Okla., where 75 third-graders were believed to have been huddled when the tornado struck.

"We were over there searching for her for an hour," the mother of a Plaza Towers student told CNN in an interview. "We got her. She was safe. There are still kids trapped."

The woman said she hadn't found her 17-year-old son, who attends Southmoore High School in Moore.

Plaza Towers students hugged and clung to the school's walls as the tornado roared over, KFOR-TV in Oklahoma City reported. Parents dodged downed power lines in their rush to the scene to find missing children. The school has 440 pupils in kindergarten through fourth grades, according to GreatSchools Inc., a San Francisco-based nonprofit foundation.

The Federal Aviation Administration confirmed that it restricted flights over the damaged area so rescue crews could better hear people buried in the rubble at the schools.

Near storm-damaged Briarwood Elementary, with 650 children in pre-kindergarten through sixth grades, a home became an impromptu shelter for at least 15 students as parents rushed to collect youngsters, according to KFOR.

The tornado was at least 1 1/4miles wide and raked the adjacent cities for 40 minutes, said Jerry Lojka, a spokesman for Oklahoma Emergency Management. Other estimates varied from a half-mile to a mile wide.

The storm was so intense "you've got to be underground to be safe," said U.S. Rep. James Lankford, an Oklahoma Republican whose district includes parts of the area.

Rescuers from across Oklahoma were headed to help in the search, Lojka said.

"Our resources are going to be stretched pretty thin, and our responders are going to be challenged," Lojka said.

Moore's Warren Theater was set up as a triage center, and the American Red Cross opened three shelters for evacuees.

Oakcrest Church of Christ in Oklahoma City was still housing evacuees from a storm earlier this month and threw its doors open again today. A group of quilters who usually donate their work to local boys' and girls' homes brought their wares to the church so displaced residents would have blankets tonight, said Christyann Anderson, the assistant to Pastor Ben Glover.

Members brought in water, Gatorade and clothes, and were working to organize donated dinners, Anderson said in a telephone interview while the pastor spoke with another reporter nearby.

Chesapeake Energy Corp. is "looking at opportunities to bring equipment, people and other expertise to help" with tornado recovery efforts, said Michael Kehs, a spokesman for the Oklahoma City-based company. Chesapeake, the second-largest U.S. natural gas producer, has about 4,000 employees in the metropolitan area, Kehs said.

The University of Oklahoma in nearby Norman opened its dorms to displaced families.