Principals in New York City were encouraged to review safety measures, which include posting security officers in lobbies and requiring identification from all visitors.
The Chicago school district urged principals to conduct lockdown drills for students, with reminders to stay low and quiet and to turn off classroom lights. Parents, teachers and school administrators in Newtown, Conn., confront the most immediate and raw tasks of helping children respond to the horrifying killings of 20 children at Sandy Hook Elementary School on Friday. But across the nation, as schools prepared to resume on Monday, officials and parents spent the weekend worrying not only about how to talk to students about what happened, but also how best to discourage it from happening again.
Tom Boasberg, the superintendent of schools in Denver, said he had not yet determined whether to ramp up drills. "When you read the story of what happened at Sandy Hook, you realize, 'Holy cow, they did a lot of things right,"' he said.
As in Newtown, Boasberg said, many Denver schools already have intercoms, buzzers and surveillance cameras mounted at their primary doors, and voters passed a bond measure last month to raise money so all campuses could have security equipment. But he added, "We're not going to turn our schools into police bunkers."
School officials in Newtown announced Sunday that students from Sandy Hook Elementary would be relocated indefinitely to an unused school in a neighboring town, Monroe.
Newtown officials said all of the district's schools would be closed on Monday, though they would continue to offer counseling. Students were invited to spend time on Monday at a local sports center to see their friends and play games.
Parents and school leaders were concerned about how to help children talk about their emotions or deal with questions that nobody will be able to answer.
In the Sandy Hook firehouse on Friday, Rashi Ray was one of the lucky ones. She flew to her 7-year-old son, shaken with fear from the long wait and almost trembling with joy at the sight of him.
At home, her son, Saahil, napped, something he had not done since he was a toddler. Ray let him sleep, knowing there was worse to come. What would she tell him about his principal, his friends, his school?
"He's just a 7-year-old boy," she said. "And slowly, he has a lot of questions, so we try and answer them to the best of our ability."
Many schools and districts around the country sent out letters to parents over the weekend with advice on how to talk to children about violence and trauma. Psychologists, social workers and counselors are preparing to fan out across schools on Monday.
At Harvard/Kent Elementary School in Boston, Jason Gallagher, the principal, said teachers will be encouraged to talk about safety at "open circle" meetings with students, but for children from kindergarten through third grade, teachers were asked not to specifically mention the events in Newtown.
"There are a lot of tricky places that it could take you," Gallagher said. If children bring it up - because they have seen news reports, talked with their own families, or exchanged rumors on the playground - he said teachers will be instructed to keep conversations focused on general safety principles or to let the children guide discussions with questions like "Can you tell me how that made you feel?"
He added that he was dispatching art, gym and other specialized teachers to join classroom teachers in the morning so that no instructor would have to confront difficult questions alone.
Throughout the weekend, parents were making their own delicate calculations of whether or how much to talk to their children about the shooting. In some cases, decisions were forced upon them. Shannon Casey, a community organizer and mother of two in Mountain View, Calif., said that by the time she picked up her 12-year-old daughter at school on Friday, she had already seen the news on her iPad.
Casey said she advised her daughter to avoid constantly reading about the tragedy on social media, and reminded her 9-year-old son about what to do in the event someone showed up with a gun. She also talked to them both about "the heroism of the teachers and how much their teachers show up for them on a daily basis and will protect them if something happens."
Tenecia H. Valerio, a mother of three children ages 6 and under in Summit, N.J., said she initially vowed not to tell them anything. But she found herself tearing up throughout the day on Friday and finally decided to tell them she was so sad because "a whole bunch of people had died."
Her family made a memorial with candles and stuffed animals to set on their porch, and she planned to keep it at that. But when her 6-year-old son started asking more detailed questions, she told him that a "man did a really horrible, mean thing and he went to the school and he hurt and killed people including little children."
"I would rather me explain it to him as a mother and be there to help him process the information," Valerio said, "as opposed to him hearing it somewhere else and me not being able to talk to him or give him a hug when he needs it."
As it was, Valerio's son responded with the heartbreaking innocence of a 6-year-old. "He said, 'I'm glad my school has a camera and a buzzer,"' Valerio recalled. And then he asked: "'Can we get Dunkin Donuts?"'