In Pakistan, an exodus that is beyond biblical

The language was already biblical; now the scale of what is happening matches it. The exodus of people forced from their homes in Pakistan's Swat Valley and elsewhere in the country's north-west may be as high as 2.4 million, aid officials say. Around the world, only a handful of war-spoiled countries – Sudan, Iraq, Colombia – have larger numbers of internal refugees. The speed of the displacement at its height – up to 85,000 people a day – was matched only during the 1994 genocide in Rwanda. This is now one of the biggest sudden refugee crises the world has ever seen.

Until now, the worst of the problem has been kept largely out of sight. Of the total displaced by the military's operations against the Taliban – the army yesterday claimed a crucial breakthrough, taking control of the Swat Valley's main town, Mingora – just 200,000 people have been forced to live in the makeshift tent camps dotted around the southern fringe of the conflict zone. The vast majority were taken in by relatives, extended family members and local people wanting to help.

But this grassroots sense of charity is slowly starting to show real strain. In a week when the relentless danger of the militants was underlined by a massive car bomb in the city of Lahore that killed at least 30 people and injured hundreds more, aid groups have warned that the communities taking people in – already some of the planet's poorest people – could themselves be displaced as they desperately sell their few assets to help the homeless.

In these "homestay" situations, some that exist purely because of tribal links between the displaced and those opening their doors, anywhere from 10 to 15 people are crowded into one room. A single latrine is shared by, on average, 35 people. Aid groups have called for a large and immediate injection of funds to help these host families who have stood forward to help those with nothing.

Graham Strong, the country director of the charity World Vision, said: "Families have provided refuge for up to 90 per cent of those escaping the fighting. They are sharing their homes, food, clothes and water. They are poor already and are making themselves poorer in the process. As the disaster continues, hosts are having to sell their land, cattle and other assets at far less than the market value to keep providing for their guests. The cultural ethic of generosity and hospitality means hosts are now facing the agonising choice between asking guests to leave and becoming destitute and displaced themselves."

Among those facing possible destitution as a result of his kindness is Rizwan Ali, 59, who lives in a village in the Buner district – another of the areas from which the military has been involved in a major operation against militants. When he heard about the countless people from nearby villages being forced to flee, he sent a truck to collect them. Now he shares his home with 37 strangers.

Confronted with this massive influx, Mr Ali – not his real name – has already sold a portion of his land to meet the additional burden. He has watched as other villagers, taking people in, have been pushed to the brink of impoverishment. He says they now face having to ask their guests to leave – something he would be loathe to do.

"It would be easier to die than to ask displaced people to leave for the camps. It will be heartbreaking and will feel as though the earth has caved in on us," said Mr Ali, who is already helping to look after the newborn baby of his daughter-in-law, who died in childbirth. "I'm exhausted, we have to play so many roles – host, provider, security, breadwinner," he told aid workers.

Confronted by such circumstances, many of the host families of Pakistan's North-West Frontier Province (NWFP) have been selling cattle at a mere fraction of their normal value to raise funds. Others are pawning gold and jewellery for as little as 5 per cent of what it would usually generate. Certainly, those who arrived came with nothing, depending entirely on the generosity of their hosts.

"Our host has done a beautiful thing in taking us in and providing for us," said one man staying at Mr Ali's house. "He has given us food and shelter but most of all he has given us our dignity."

One man, aged 90, said that because there had been no warning to leave, when the gunfire erupted around them they gathered what they could carry and fled. "Many of us didn't even have any shoes. We walked [13 miles] on mountain paths. It took the whole day," he said.

Another of those staying with Mr Ali is 12-year-old Saima. "I don't know where my friends are. We were separated when we left," said the young girl, who is helping to care for the household's newborn baby. "It was scary when we ran. It was like my heart was beating in my feet as we ran. There was a time I couldn't walk another inch because of ulcers under my feet, but the fear kept us going somehow."

For all the humanitarian problems that the military operation against the Taliban has created, the Pakistani army and the government of Asif Ali Zardari believe they have no alternative but to carry on and try to crush the militants, who had taken control of several areas barely 60 miles from Islamabad. Under considerable international pressure, the military launched the operations earlier this month after a controversial ceasefire deal – under which the government allowed the operation of Islamic law, or sharia, in parts of the Swat Valley and elsewhere – fell apart.

The military claimed a strategic victory yesterday, saying it had taken control of almost all of Mingora. While troops were still meeting pockets of resistance on the outskirts of the town, Mingora itself was under the full control of the military, said a spokesman, Maj- Gen Athar Abbas. "As far as Mingora city, security forces have taken over," he said. "There are still pockets of resistance. They are on the periphery of Mingora city."

In addition to the humanitarian problem, of course, the military operation – which it claims has so far killed anywhere up to 1,100 militants – has already apparently led the Taliban into revenge attacks. After militants launched a gun and bomb attack on police and intelligence offices in Lahore last week, a spokesman for Baitullah Mehsud, one of the senior Taliban leaders, claimed responsibility and said the devastating attack – the third major incident in the Punjabi capital this year – had been carried out in response to what has been happening in Swat. The Taliban also threatened more attacks, raising the prospect of a fresh wave of suicide attacks in Pakistan's major cities. The following day, at least 14 people were killed in suicide bombings in Peshawar.

Hakimullah Mehsud, a commander loyal to his namesake, told reporters: "We have achieved our target. We were looking at this target for a long time. It was a reaction to the Swat operation. We want the people of Lahore, Rawalpindi, Islamabad and Multan to leave those cities as we plan major attacks against government facilities in coming days."

Yesterday, Pakistan's Prime Minister, Yousuf Gilani, defended the decision to launch the offensive, saying that the authorities had no genuine alternative.

"The very existence of Pakistan was at stake. We had to start the operation," he said. While speaking to workers at state-owned Pakistan Television, Mr Gilani also promised payments of cash to help the hundreds of thousands of people forced from their homes, as well as a massive reconstruction.

Such words, had they learned of them, would have been welcome to Rizwan Ali and the 37 people – strangers until this military operation began – squeezed into his home.