A Pakistani army offensive against the Taliban in Swat Valley in North West Frontier Province has sparked a mass civilian exodus from the former tourist region, raising fears of a protracted humanitarian crisis.
Following are questions and answers about the plight of the hundreds of thousands forced to flee their homes and those still trapped in the battle zone.
HOW MANY CIVILIANS HAVE BEEN DISPLACED?
According to the United Nations Refugee Agency (UNHCR), over 501,400 people have fled Swat Valley since fighting began on May 2.
This is on top of around 556,540 civilians forced to leave Pakistan's Federally Administered Tribal Areas (FATA) due to fighting between government troops and pro-Taliban militants in August last year.
Relief organisations are therefore trying to respond to the needs of over one million people Â?the biggest ever internal displacement in the country.
Around 20,000 registration forms are being printed daily as people continue to stream out of the conflict area.
But the numbers only account for those who've registered. Aid agencies believe there are possibly hundreds of thousands who have not yet registered in camps or at one of 38 UNHCR registration points.
The United Nations estimates it will have to respond to the needs of 1.5 million displaced people.
WHERE ARE THESE DISPLACED PEOPLE?
About 72,700 Â? around 15 percent Â? of those who have fled in recent days are living in camps in neighbouring districts.
The largest numbers of internally displaced people (IDPs) are concentrated in Mardan district. But many are also seeking refuge in Swabi, Peshawar, Charasadda, Nowshera and Kohat areas.
Aid workers say the majority of displaced are reluctant to live in formal camps for cultural reasons as they feel their dignity is being compromised and that women cannot strictly observe 'purdah' where they should be separated from men.
As a result, nearly 428,800 people are living with host communities or relatives, in schools, colleges, community guesthouses, rental accommodation and also spontaneous informal settlements in places like flour mills, stadiums and parks.
Many of those displaced have travelled long distances by foot or in the back of trucks and lorries with no more than the clothes they are wearing. They are arriving from the three conflict areas of Swat, Buner and Lower Dir exhausted and traumatised by the fighting and having left behind loved ones.
The United Nations estimates nearly half the IDPs are women, and another 20 percent are children under five.
WHAT ARE THE CONDITIONS IN THE CAMPS?
There are currently nine camps. Aid agencies say many are overcrowded and people are living in hot, cramped conditions with limited clean water and food.
ActionAid says people are becoming increasingly agitated by the scarcity of relief. The NGO adds that registration is problematic as people have to wait in long queues in the sweltering heat, sometimes fruitlessly. It says registration requires identity documents, but some left their homes too hurriedly to bring these with them and many, particularly women, do not have ID cards in the first place.
Health workers say the lack of shelter, food, sanitation and clean water combined with the approach of the monsoon season is increasing the risk of diseases such as acute watery diarrhoea, malaria and respiratory infections.
According to Islamic Relief, many of the children are suffering from psychological trauma and are at risk from serious health problems.
WHAT ARE THE CONDITIONS FOR THOSE OUTSIDE THE CAMPS?
With more than 80 percent of the displaced living outside formal camps, aid workers say it is essential that these communities receive relief.
The United Nations infrastructure needs to be strengthened in towns where the displaced are arriving to ease the burden on local services.
In many cases, up to 30 people are living in one room. Others are crowded into schools and community guest houses where there's a shortage of food and water and inadequate sanitation. Those in rented accommodation are forced to pay extortionate rates.
Accommodation in the towns is becoming scarce and relief agencies estimate that 200,000 people will have to seek refuge in the camps, where there are already almost 630,000 people.
HOW ARE AID AGENCIES COPING WITH THE MASS EXODUS?
The crisis is posing huge challenges for the government and humanitarian community. Aid agencies say they expected a fallout from the fighting but were not prepared for the scale of the crisis and speed with which it escalated.
The U.N. Children's Fund (UNICEF) says it has already exhausted its contingency stockpiles and desperately needs to replenish stocks of water purification chemicals, jerry cans and other essential non-food items. They also say there is a desperate need to set up schools for children who need some normality after their experiences.
The World Food Programme says it has enough wheat, pulses, and other staples to feed 1.5 million people for three months, which may not be enough to deal with the crisis. The World Health Organisation warns there's a serious risk of disease outbreaks and malnutrition.
The UNHCR is airlifting in tonnes of supplies but says more camps are needed. Four of the nine camps are now full. UNHCR planners are assessing sites for new camps but say there's a scarcity of free land.
Relief workers say the situation requires immediate international response. A U.N. appeal was launched in September 2008 for those displaced by fighting last year, but it has so far received only 47 percent of the $166 million required. The United Nations is planning to launch another emergency appeal next week.
The government has allocated one billion rupees ($125 million) for relief efforts but experts say this is only a fraction of the money required. Prime Minister Yusuf Reza Gilani says the government is planning a donors conference. Foreign donors have started coming forward with pledges but aid workers say it is a race against time.
WHAT ABOUT THOSE TRAPPED IN THE BATTLE ZONE?
The estimated population in Swat, Buner and Lower Dir is believed to be around 3.3 million. Aid agencies estimate at least 2 million remain trapped by the fighting.
The government has twice relaxed a curfew to allow people to leave the area. But many have not been able to get out - too poor to afford transportation or too old to make the journey. Others are reluctant to leave their homes and land. Aid workers also say people have left children behind in the chaos as they fled air strikes.
There are no aid agencies in the area due to the intense fighting. Roads are also blocked, preventing relief supplies getting in.
The International Committee for the Red Cross (ICRC) says trapped civilians are cut off from basic services, including health care.
In Mingora, the Swat district's main hospital has been abandoned, and water and electricity have been cut off for days. Many people have reportedly moved to Upper Swat to stay with relatives in rural areas, only to find there is heavy fighting there as well.
The ICRC says while both parties have agreed in principle to allow the agency to operate in those areas, the intensity of the fighting has prevented it from doing so. It says it will assess the humanitarian situation and evacuate casualties to its Peshawar hospital as soon as the situation permits.
Pakistani authorities report civilian casualties but there is little information on the numbers killed or injured.
There has been talk between the government and relief agencies of how to get relief supplies into the area and evacuate those who are wounded through a humanitarian pause which would allow for the establishment of a humanitarian corridor.
WHAT ARE THE LONGER TERM PROSPECTS?
The United Nations has warned of a protracted humanitarian crisis for a country already being propped up by a $7.6 billion International Monetary Fund loan.
The ICRC says the massive and unprecedented displacement means long-term assistance from humanitarian agencies will be required.
The majority of displaced are farmers who have fled during harvest season and if they do not reap their crops now, they will be without livelihoods for at least a year. They will therefore require support over the medium to long-term.
Humanitarian organisations will also need to take into account the burden on communities hosting many of the displaced in their longer-term response.
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