GILGIT, August 4, 2008 (AFP) - Pakistani army helicopters airlifted two frostbitten mountaineers from K2 and tried to save another Monday after a catastrophic ice fall on the world's second highest peak killed 11 climbers.

The avalanche is believed to be the deadliest single incident on the 28,251-foot (8,611-metre) Himalayan peak, which is widely acknowledged as far harder to scale than Everest with a fatality rate almost five times as high.

'Two Dutch climbers were brought by our people and their colleagues down to base camp from an altitude of 7,300 metres overnight,' army officer Captain Azimullah Beg told AFP by satellite telephone from K2 base camp.

'They were then picked up by army helicopter from base camp this morning and have now been shifted to hospital for treatment for severe frostbite,' said Beg, identifying the climbers as Wilco Van Rooijen and Cas van de Gevel.

A second chopper went up to help a stranded Italian but could not touch down and returned after a brief contact with the climber, Pakistani mountain guide Sultan Alam said.

'Our four high-altitude porters left a while ago and it is expected that they will bring the Italian climber down this evening,' he told AFP from base camp, as the roar of a helicopter could be heard in the background.

The Italian, Marco Confortola, was unable to walk because of frostbite in his leg, officials said. Alam said he was getting food and drink from a Singaporean expedition in the area.

All three climbers were 'badly affected and it appears that at least one of them would have his hand and leg chopped off. This is what our high altitude doctors believe,' Alam said.

The climbers who died in Friday's avalanche were three South Koreans, two Nepalis, two Pakistanis, a Serbian, an Irishman, a Norwegian and a Frenchman, Alam and Beg said.

The disaster happened when a pillar of ice broke away in a steep gully known as the Bottleneck near the summit and swept away fixed lines used by the mountaineers as they made their descent on Friday.

'At least 11 climbers have died. This is one of the worst incidents in the history of K2 climbing,' Alam said.

The deadliest year to date on the peak on the Pakistan-China border was in 1986, when 13 climbers died in a series of incidents.

An Austrian climber at K2 base camp said he was aware of 12 deaths resulting from Friday's avalanche.

'The mood at the camp is obviously very low,' Christian Stangl was quoted as saying by Austria's APA news agency. 'Every expedition has lost at least one or two people.'

In Seoul, a mountaineering club on Monday confirmed that three South Koreans and two Sherpas were among those killed, and another two Korean climbers got to base camp before the avalanche struck.

The survivors had suspended attempts to recover the bodies of their colleagues due to the 'hopeless' weather conditions, Cho Hyung-Gyu, president of the country's southeastern Kyongnam mountaineering club, told AFP.

A Swedish climber who survived said he feared for his life when a Pakistani climber fell on top of him.

'I have carried down both living and dead people from the mountain,' the climber, Fredrik Straeng, told the Swedish news agency TT, also putting the death toll at 11.

'I was terrified that (the Pakistani) would pull us all off the cliff and screamed to him to use his ice axe, but he lost his grip and plummeted off a 300-metre cliff,' Straeng said.

He said a large number of climbers decided to leave their camp at just over 7,000 metres before disaster struck to try to reach the summit after the skies cleared following a long period of poor weather.

'We had a feeling this would not turn out well and decided to turn around. The accident could have been prevented. These mountains lure out way too inexperienced and naive people,' he said.

Missing Irishman Gerard McDonnell, 37, an Alaska-based oil worker who has climbed Everest, was given up for dead by experienced mountaineering friend Pat Falvey.

Norwegian media reported that Rolf Bae, 33, died in the disaster, while his wife was reportedly trying to make her way down with two other Norwegians.

Italian climbers Achille Compagnoni and Lino Lacedelli first scaled K2 on July 31, 1954. Between that first ascent and 2007, there were 284 successful ascents and 66 fatalities.

In the same period, Everest was summited 3,681 times, with 210 deaths.