* Helicopters fly troops into Taliban stronghold
* Estimated 800,000 civilians have fled latest crisis
* Militants "on the run," military says
* Military says 751 militants, 29 soldiers killed
* U.N. sees huge humanitarian challenge (For further Pakistan coverage, click on [ID:nSP102615])
(Adds comments at U.N. by Zardari, Ban Ki-moon)
By Junaid Khan
KOTA, Pakistan, May 12 (Reuters) - Helicopter-borne Pakistani soldiers swooped into a Taliban stronghold in a remote corner of Swat on Tuesday as the United Nations urged help for hundreds of thousands displaced by the fighting.
The offensive in Swat, 130 km (80 miles) northwest of Islamabad, is seen as a test of the government's commitment to face up to a growing Taliban insurgency and comes after the United States accused it of "abdicating" to the militants.
The fighting has caused civilians to flee the valley, once a tourist destination, raising fears of a humanitarian crisis.
A senior military official overseeing help for the displaced said about 800,000 civilians had fled from the latest fighting. They were joining about 500,000 displaced by earlier fighting in the northwest, said Brigadier Aamir Raza Qureshi.
On Tuesday, helicopters flew soldiers into the Peochar valley, which runs northwest off the main Swat valley, where the Taliban have a headquarters, the military said.
"Their mission is to conduct search and destroy operations," military spokesman Major-General Athar Abbas told a briefing. "The militants are on the run."
Residents said troops had also been seen moving on the ground towards Peochar.
The offensive was launched last week when President Asif Ali Zardari, the widower of former Prime Minister Benazir Bhutto, was in Washington assuring a nervous United States his government was not about to collapse and was committed to fighting militancy.
A February pact aimed at ending violence in Swat, which effectively handed the militants control, had raised fears of a gradual Taliban takeover of more areas in the nuclear-armed country, which is vital to U.S. efforts to defeat al Qaeda and stabilize Afghanistan.
At the United Nations on Tuesday, Zardari said after talks with Secretary-General Ban Ki-moon that the U.N. chief would "appeal to the world with us jointly to help Pakistan and the affectees of this war."
"Our basic purpose today is to draw attention to ... the human catastrophe that is taking place because of this war effort," he told reporters. "We want the world to help us."
Ban said the United Nations was ready to step up aid, but he had voiced concern to Zardari over the plight of civilians. "I expect President Zardari to take all necessary care to protect the civilian population," he said, adding the Pakistani leader had assured him aid would be delivered smoothly.
PROTRACTED CRISIS
Military spokesman Abbas said 751 militants had been killed in the offensive while 29 soldiers had been killed and 77 wounded. Most reporters have left Swat and the estimate of militant casualties could not be independently confirmed.
Taliban spokesmen were not available for comment.
There were also clashes in Imam Dehri, the home town of Fazullah, the Taliban chief in Swat. Four militants were killed there, Abbas said.
In all, about 15,000 members of the security forces are facing about 5,000 militants in the region, the military says.
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 U.N. refugee agency has opened stockpiles of supplies to help the displaced and is airlifting in tons more supplies.
"The speed and scale of this crisis is posing huge challenges for the government and the humanitarian community," U.N. High Commissioner for Refugees spokesman Ron Redmond told a news briefing in Geneva.
Richard Holbrooke, U.S. special envoy for Afghanistan and Pakistan, told a Senate panel in Washington, "We have a major, major refugee crisis" and the State Department was discussing adding to the more than $57 million Washington had provided.
"Since our national security interests are so at stake and we look like we're heading for about 1 million to 1.3 million refugees, we should not ignore that," he added.
The World Food Program said it had 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 Organization warned that the displaced faced serious risks of disease outbreaks and malnutrition.
Prime Minister Yusuf Raza Gilani told the National Assembly on Monday that the government would soon organize a conference of aid donors to marshal funds.
Most political parties and many ordinary people support the offensive, but that could change if civilians displaced in what the government say is the country's largest-ever internal migration are seen to be suffering or if many are killed.
Stock market investors have been unnerved by the fighting and political tension in the commercial hub of Karachi but the main index rose 2.44 percent on some aggressive buying by government institutions, dealers said.
Separately, suspected U.S. drone aircraft fired missiles in a Pakistani region on the Afghan border, killing at least eight people, military and intelligence officials said.
The attack took place in a mountainous region of South Waziristan, a known al Qaeda and Taliban hotbed, they said. (Additional reporting by Kamran Haider, Alamgir Bitani, Faisal Aziz, Paul Eckert in Washington and Patrick Worsnip at the United Nations; Editing by Alex Richardson and Cynthia Osterman)
'''W wyniku operacji ''Czarna Burza'' toczącej się w Dolinie Swat od 26 kwietnia, ze swoich domostw uciekło już ponad pół miliona cywili. Wczoraj po południu dokładnie było ich  670 906.'''

W wyniku zaostrzenia operacji 2 maja rozpoczęła się wielka ewakuacja cywilów z miast z Doliny Swat. Wcześniej do końca kwietnia z stref walk uciekło ponad tysiąc osób. 8 maja odnotowano 78 tys. uchodźców - większość to mieszkańcy Mingory, która jest nadal oblegana przez siły pakistańskie. 10 maja anulowano na siedem godzin godzinę policyjną w miastach Doliny, by umożliwić ucieczkę cywilom. W ten dzień do 8 obozów uchodźców zorganizowanych przez UNHCR uciekło 360 tys. cywilów. W wyniku krwawych strać 12 maja liczba uchodźców w obozach ONZ przekroczyła pół miliona - 501 496 uchodźców. Mimo iż w prowincjach gdzie toczyła się operacja wprowadzono godzinę policyjną to cywile nadal masowo uciekali z miejsc zamieszkania. Dnia 13 maja liczba uchodźców osiągnęła 670 906.

Z kolei od sierpnia 2008, kiedy to rozpoczęły się ciężkie walki na północno-zachodnim Pakistanie, liczba uchodźców osiągnęła 1,248,715.

Tymczasem 12 maja armia pakistańska podała, że zabiła 751 bojowników talibskich od początku operacji, przy czym straciła 29 żołnierzy.

W walkach o kontrolę nad Doliną Swat, gdzie od 13 kwietnia obowiązuje prawo szariatu walczy ok. 15 Pakistańczyków i 5 tys. rebeliantów.