PESHAWAR, Pakistan: A Pakistani teenager killed when he tackled a suicide bomber at the gates of his school is being hailed as a hero for saving "hundreds" of lives.

Fifteen-year-old Aitzaz Hassan, a ninth grader, died in hospital after a bomber blew himself up when the teen stopped him from entering his school in Ibrahimz in the Hangu district in northwestern Pakistan on Monday.

Police official Shakirullah Bangash told Agence France-Presse that Aitzaz intercepted the bomber some 150 metres from the main gate of the school, where the media reported almost 2,000 students were gathered, most of them Shiite, and were the target of the attack.

News of Hassan's bravery has prompted an outpouring of tributes on social media.

Sherry Rehman, Pakistan's former ambassador to the United States, tweeted: "Hangu's shaheed (martyr) Aitzaz Hasan is Pakistan's pride. Give him a medal at least. Another young one with heartstopping courage #AitzazBraveheart."

Another police official, Ali Murtaza, told Dawn, an English-language Pakistan newspaper, that the suicide bomber was walking towards the school at around 8am on Monday when the assembly was being held in its main ground.

Hangu borders one of Pakistan's seven lawless tribal districts on the Afghan border considered to be the hub of militants.

The district has a history of sectarian violence, with Sunni terrorists linked to Al-Qaeda and the Taleban often attacking gatherings by Shiites, who comprise about 20 per cent of the country's population.

Eyewitnesses said Aitzaz was with friends, the BBC reported, when they became suspicious of the way moved and asked him to stop.

When the bomber kept on moving towards the school, Aitzaz hurled a big stone at the bomber but he missed the target.

Then Aitzaz he decided to confront and capture the bomber, despite the pleas of his friends. When Aitzaz grabbed the bomber, they said, the bomber detonated his vest the bomber blew himself up.

The eyewtinesses said that by doing so he saved the lives of hundreds of students and their teachers were saved. The police official also said Aitzaz had sacrificed his life to save other students.

His father Mujahid Ali Bangash, 55, told AFP he felt not sadness but pride at his son's death.

"Aitzaz has made us proud by valiantly intercepting the bomber and saving the lives of hundreds of his fellow students," he said. "I am happy that my son has become a martyr by sacrificing his life for a noble cause."

Bangash works in the UAE and was only able to reach Ibrahimzai village, an area dominated by minority Shiite Muslims, the day after his son's funeral.

"Many people are coming to see me but if they try to express sympathy, I tell them to congratulate me instead on becoming the father of a martyr," he said. "I will be even more than happy if my second son also sacrifices his life for the country."

Hassan's cousin Mudassir Bangash described Aitziz as an accomplished student who excelled in all extracurricular activities.

"Aitzaz was a little plump and we used to call him pehlwan (wrestler)," he told AFP.

"My cousin wanted to become a doctor but it was not God's will."