NEW YORK: Students at the elementary school where a gunman massacred 26 children and teachers last month were returning Thursday to classes at an alternative campus described by police as “the safest school in America.”

Sandy Hook Elementary School in Newtown, Connecticut has been closed since the Dec 14 tragedy in which a 20-year-old local man shot 20 small children and six staff members before committing suicide.

Survivors were finally to start their new academic year in the nearby town of Monroe, where a disused middle school has been converted and renamed from its original Chalk Hill to Sandy Hook.

Newtown schools superintendent Janet Robinson told a televised press conference near the school on Wednesday that some 80 people worked at transforming the building into “a very cheerful elementary school.”

“It has been renamed Sandy Hook School, so we can carry on our traditions,” she said. “The children are coming in. They're so excited to see the teachers. The students coming back to school completes a circle.”

To ease the transition for traumatised witnesses of the massacre, teachers have brought with them furniture and belongings from the old school, Robinson said.

Lieutenant Keith White, from the Monroe Police Department, told the press conference that numerous extra security measures were being taken, including “stopping every vehicle that comes onto the campus.”

“I think right now it has to be the safest school in America,” he said.

Families were invited to inspect the campus on Wednesday and acting principal Donna Page, who replaces the slain school head Dawn Hochsprung, said “the facility is safe, secure and fully operational.”

Page said parents would be allowed to stay in the school when it opens for classes, to provide reassurance to their children.

“We understand many parents may need to be near their children on their first day(s) of school and you will be welcome. That being said, we encourage students to take the bus to school in order to help them return to familiar routines as soon as possible,” she wrote.

The shootings, in which the killer wielded a semi-automatic assault-style rifle, provoked a major national debate on gun control and a promise from President Barack Obama to back a bill outlawing military-type weapons.

The shooter, Adam Lanza, was laid to rest over the weekend after his father, a tax executive, retrieved his body from the authorities last week, a family spokesman said.

Lanza's mother, whom he shot at their home just ahead of the school massacre, was buried in New Hampshire last month.