HER name was Sahin and, in a matter of hours, her world had been broken.

As fighting raged in their hometown of Mingora ? fighter jets screaming overhead and mortar fire pounding ? she and her husband tried to escape with their 10 children. Amid the chaos, her husband was killed by an artillery shell. There was hardly time to bury him in the courtyard of a neighbour's house before Sahin was forced to think of the children and of somehow leading them to safety by herself. They walked for "hours and hours" before, in a neighbouring town, they found a bus. That bus brought them to a camp for the displaced, a place for the beleaguered, for those with nowhere else to go.

Now huddled with her six girls and four sons – three of whom are disabled – Sahin, in her early 50s, can barely think of the future. "Even if the conflict stops, we cannot go back as the house has been destroyed," she said, her family carrying barely more than the clothes they were wearing when they fled.

Across a 50-mile swath of northwest Pakistan, there are countless similar stories to that of Sahin. As the Pakistan military mounts what appears to be a major operation against Taliban fighters who have seized control of several districts little more than 60 miles from the capital, Islamabad, aid groups have warned of a human tide of up to 500,000 people fleeing their homes. The UN said an estimated 200,000 have fled the Swat valley and its main town, Mingora, in the last few days alone, while another 300,000 are poised to flee if they get the chance. This would create a total of 1m people forced from their homes by fighting in the past 12 months. It represents the biggest internal displacement of people since Pakistan secured independence more than 60 years ago.

"People are in shock. In some cases, their homes have been destroyed by mortar shells. They are wondering when they'll be able to go back. Others say they will not be able to go back," said Antonia Paradela, an official with Unicef at a refugee camp south of the Swat valley. "This is the place where the families are coming. They are tired, sweaty, dusty. There are whole families crying because they have lost someone. But there is also a sense of relief to be out of the danger."

Under mounting international pressure, the government of Asif Ali Zardari and Pakistan's military launched last week's operation to drive the Taliban from the former tourist destination of Swat after a controversial, three-month ceasefire with the militants fell apart. After a previous military effort failed to dislodge the militants who had extended their violent influence throughout the valley over a two-year period, the government in February signed a peace deal which included an agreement to establish Sharia courts in Swat and some neighboring areas.

The Taliban, however, failed to meet its end of the agreement and lay down its arms. Indeed, emboldened by the government's acquiescence, the militants then spread from Swat into the neighbouring and strategically important Buner valley. The army is also battling to drive out the Taliban from Buner and nearby Lower Dir.

While journalists are effectively prevented from reaching the war zone, the military's operation ? which involves more than 5,000 troops pitched against an estimated 5,000 Taliban fighters ? appears unexpectedly firm, and yesterday officials said that 140 militants had been killed in the past two days. Some observers, however, wondered whether the army, traditionally trained and prepared to fight a conventional war against India, had the will or capability to effectively confront a well-trained, well-armed guerilla enemy.

There was also speculation whether, in the week that Barack Obama outlined his new 'Af-Pak' strategy to Zardari and Afghan leader Hamid Karzai in Washington, there may have been a reluctance to fight what could have been seen as another battle in America's war. The Obama administration's ongoing policy of using missiles fired from unmanned drones at suspected militant target, and the subsequent civilian "collateral damage" this causes, is hugely unpopular in Pakistan

Yet this time, several things appear different. From the start, the battle for Swat has been pitched as a battle for the future of Pakistan ? and one that has been directed by the Pakistani authorities rather than Americans. In a televised address on Thursday as the military operation was formally announced, prime minister Yousaf Gilani, said: "In order to restore honour and dignity of the country, the armed forces have been called in to eliminate militants and terrorists. We will eliminate those who have tried to destroy the peace of the country."

The seemingly widespread support for this operation, as opposed to Washington's drone strikes, appears based in a large part on growing public dismay with the Taliban. With the Taliban having embarked on a policy of burning girls' schools and beheading their opponents only to be "rewarded" with a deal that saw Sharia law enacted, the Pakistani public has growing increasing anxious as the militants' threat has increased rather than reduced.

For now, however, the army says it is determined to succeed. "The army is now engaged in a full-scale operation to eliminate the militants, miscreants and anti-state elements from Swat," said the army's spokesman, Maj Gen Athar Abbas.

The result of this is that in the coming days there are likely to be hundreds of thousands more people like Sahin rushing desperately out of Swat and towards the refugee camps and reception centres that have been established at the southern end of the valley.

Sahin, her children and some other members of her family are in the category of those who have nowhere else to go. Five months ago, when an earlier spike in violence also drove them from Swat, they were able to stay with relatives in Peshawar. This time, that option was not available to them, she said. For now the family must sit amid the tents of the camp at Sheikh Shehzad, waiting, wondering.