Security detail ... Pakistani students walk to school as a soldier stands guard outside the Army Public School which was targeted by Taliban militants in December. Picture: AP Photo/Mohammad Sajjad Source: AP

The December 16 attack on the Army Public School in Peshawar claimed the lives of 150 people, mostly children, and prompted a bout of national soul-searching even in a country used to high levels of violence.

Across the country, schools had remained shut for an extended winter break as authorities strengthened security and announced new measures including the death penalty to combat insurgents. Most reopened on Monday along with the army school in the north-western city.

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Moving on ... survivors of Pakistan’s worst-ever militant attack have returned to the school. Picture: AFP/A Majeed Source: AFP

High security ... Pakistani security staff member searches the bags of students entering a government school after schools reopened. Picture: AFP/Hsham Ahmed Source: AFP

For 16-year-old Shahrukh Khan, who was shot in both legs while pretending to play dead in his school’s auditorium, going back was traumatic.

“I have lost 30 of my friends. How will I sit in the empty class, how will I look towards their empty benches?” he said before the school reopened.

“My heart has been broken. All the class fellows I had, have died. Now my heart does not want to attend school.”

Back to school ... Pakistani students head back to school on Monday. Picture: AP Photo/B.K. Bangash Source: AP

At least 20 soldiers were seen at the main entrance of the Army Public School, with an airport-style security gate installed at the front.

Elevated boundary walls with steel wire fencing have been put in place in some schools around Peshawar and nationwide.

Raheel Sharif, the head of Pakistan’s powerful army, made an unannounced visit to the school.

US Secretary of State John Kerry, who is currently in Pakistan on a surprise two-day visit, is also reportedly scheduled to visit the school, according to the national security adviser to Prime Minister Nawaz Sharif.

Huge military presence ... Pakistani soldiers keep watch near Army Public School after it was reopened following an attack. Picture: AFP/A Majeed Source: AFP

Parents spoke of having to sit down with their children and mentally prepare them for their return to the school.

“He was terrified but we talked him up. We cannot keep him imprisoned between four walls and we must stand against militancy,” Muhammad Zahoor said as he walked his son along the city’s main Warsak Road.

“I want to go to school to see my friends. I will join the army after my schooling and will take revenge,” said Muhammad Zaid, his son.

Of the 150 victims killed in Pakistan’s deadliest-ever militant attack, 134 were children.

Destroyed ... 150 people, including children, were killed after Taliban militants attacked this army-run school in Peshawar. Picture: AFP/A Majeed Source: AFP

Long recovery ... a Pakistani dad wraps blanket around his son Ahmed Nawaz, 15, who survived the Peshawar school attack. Picture: AP Photo/Muhamad Sajjad Source: AP