Pakistani children and their parents have returned to the school where Taliban gunmen killed 150 of their classmates and teachers.

Their green school blazers, Superman lunchboxes and hands clutched tightly to their parents were a symbol of perseverance despite the horrors they had endured.

Pakistan has been reeling from the December 16 terrorist attack in Peshawar - one of the worst the country has experienced.

The violence carried out by seven Taliban militants has put a spotlight on whether the country can end the stubborn insurgency that kills and maims thousands every year.

The violence also horrified parents across the nation and prompted officials to implement tighter security at schools.

For parents like Abid Ali Shah, getting ready for school was horrifically painful.

His wife was a teacher at the school and was killed in the violence. Both of his sons attended the school. The youngest was shot in the head but survived after the militants thought he was dead.

His older son, Sitwat Ali Shah, said he had managed to control his emotions. It was not until he saw his brother break down in tears that he did as well.

The chief of Pakistan's army, General Raheel Sharif, was on hand inside the school to greet students.

For many, attending school was an act of defiance and proof that they would not be cowed in the face of Taliban threats to attack again.

Andleeb Aftab, a teacher at the Army Public School, lost her son, Huzaifa, in the attack.

She arrived wearing a black dress and black head scarf and walked briskly toward the school, where she had last seen her son alive.

"I have come here because the other kids are also my kids," she said.

"I will complete the dreams of my son, the dreams I had about my son, by teaching other students. I have chosen to get back to school instead of sitting at home and keep mourning."