Shot by the Taliban: the 14-year-old campaigner riding the school bus

A girl of 14 who gained worldwide acclaim for speaking out against the Pakistani Taliban's ban on education for girls was shot in the head on her way home from school yesterday.

Militant leaders said the attack on Malala Yousafzai was a warning to other "secular" youths. The teenager was sitting with other pupils in a bus ready to leave the grounds of their school when gunmen approached and asked which one was Malala. They opened fire, injuring her and two other girls in the vehicle.

The attack took place not in a wild tribal area but in the Swat Valley, a northern district where the Taliban was supposedly cleared out by the Pakistani army in 2009. Malala was airlifted from her school in the town of Mingora to hospital in the provincial capital, Peshawar, for surgery. She was in a critical condition last night but doctors said the bullet had not entered her brain.

The Tehreek-i-Taliban Pakistan (TTP) – the main faction of the home-grown Taliban – claimed responsibility for the assassination attempt and warned that it would target Malala again if she survived. Earlier this year, the TTP said the teenager was on its hitlist because of her "secular" views. A spokesman for the Taliban said yesterday: "She was young but she was promoting Western culture."

Malala had resisted the Taliban takeover of Swat with her diary – published in 2009 under a pseudonym by the BBC's Urdu language service. In it, she told the outside world what was happening in her home district. Early that year, with the Taliban menace still present, she spoke out on television, always sticking carefully to her demand only for schooling.

In one television appearance in Swat, with Taliban sympathisers apparently in the audience, she said: "I don't mind if I have to sit on the floor at school. All I want is education. And I am afraid of no one."

Malala said that her ambition was to become a politician because "this country is in crisis and our governments are lazy".

Despite relentless, violent attacks by the Pakistani Taliban since 2007, the public's views on the nature of the extremist movement are divided. Many people believe the Taliban are simply reacting to the government's support for the US presence in Afghanistan, and to missile attacks by US drone aircraft in tribal lands which are Taliban strongholds. At the weekend, Imran Khan, the cricketer turned populist politician, led a "peace march" to the edge of the tribal area, demanding that peace talks be opened with the Taliban, and calling for the end of US drone strikes.

But the attack on a schoolgirl could expose the wider agenda of the Pakistani Taliban, which is aimed at imposing medieval-style Islam on the country. Shocked by Malala's fate, politicians and the media united in strong condemnation. Hamid Mir, the country's most popular talk show host, began his programme last night with the words: "I can see the whole nation's head bowed in shame today I want to ask those who shot a girl, who only wanted to go to school, do you think you are Muslims?"

Speaking in parliament, the Prime Minister, Raja Pervez Ashraf, said: "Malala is my daughter too. She is Pakistan's daughter. If this [extremist] mindset persists, which girl in Pakistan will be safe?"

Swat, a mountainous area that was once known as a holiday resort and does not border Afghanistan, started to come under the creeping control of the Pakistani Taliban over several years from at least 2005. The extremists had completed their domination by 2007, while Pakistani authorities seemingly looked on.

In February 2009, the government, with the support of the military, signed a treaty with the Taliban that effectively handed it control of the Swat Valley.

It was only after international pressure, and the Taliban's decision to take over of the neighbouring district of Buner, that the military was forced to launch an operation in May 2009.