(Reuters) - A Pakistani military offensive against Taliban militants in their Swat valley bastion has forced about 1.5 million people from their homes, the government and the United Nations say.

A failure to respond to one of the most dramatic displacement crises in recent times could generate instability, U.N. High Commissioner for Refugees Antonio Guterres said at the weekend as he called for “massive support” from the international community.

Following are some facts about the displaced.

- The number of people displaced by the fighting has risen to about 1.5 million, the United Nations said on Wednesday.

- They are joining about 555,000 displaced by earlier fighting in the northwest.

- Many thousands of people remain in the valley and the head of the government’s relief effort said authorities were trying to ensure regular food supplies for them.

- The United Nations says about 48 percent of the displaced are children and the country faces a long-term humanitarian crisis.

- On average, about 100,000 people have been registered daily at 89 registration points, the U.N. refugee agency said.

- About 131,000 of the displaced are in 26 camps. The rest are staying with friends, relatives, in rented accommodation or in “spontaneous settlements” that have sprung up.

- Fifteen new camps set up this month are full and there is an urgent need to identify new sites and establish new camps, the U.N. refugee agency said.

- The U.N. refugee agency has opened stockpiles of supplies to help the displaced and has also airlifted in 120 tons of supplies including plastic sheets for shelters and mosquito nets.

- The U.N. World Food Program (WFP) has mobilized its in-country stocks and is feeding 900,000 people.

- The WFP has also established 17 humanitarian hubs to provide food and other help to people living with host families.

- The World Health Organization (WHO) has delivered 20 mini-emergency health kits, enough for 120,000 people for one month.

- The health situation in districts hosting the displaced remains stable although an increase in cases of diarrhea had been reported in some camps, the United Nations said on Wednesday.

- The U.N. children’s agency, UNICEF, and its partners are providing 4.5 million liters of clean water a day to about 280,000 people, while more than 6,800 latrines and 3,400 bathing spaces have been built.

- The army, which played a major role in helping survivors of a big earthquake in 2005, is donating part of its rations to the relief effort, enough to feed about 80,000 adults a day.

- The United States has offered $110 million to help the displaced. Britain has donated 10 million pounds ($15.19 million). France has promised 12 million euros and Germany 1 million euros.

- The government said on Wednesday it was providing an initial 8 billion rupees ($99 million) for relief as well as 25,000 rupees ($310) directly to every displaced family.

- Both the United Nations and the government are due to outline the needs and issue appeals for help this week.