GILGIT, Pakistan (AFP) - - Pakistani rescuers Monday saved one climber stranded on K2 and tried to help another after a catastrophic ice avalanche on the world's second highest peak killed 11 mountaineers.

Three South Koreans, two Nepalis, two Pakistanis, a Serbian, an Irishman, a Norwegian and a Frenchman were killed when a chunk of ice swept away ropes near the summit of the 28,251-foot (8,611-metre) peak on Friday, officials said.

A Dutch climber was rescued by helicopter and a missing Italian had been located but was still stuck on the mountain, widely-acknowledged by climbers to be more difficult to scale than Everest, said officials.

"At least 11 climbers have died. This is one of the worst incidents in the history of K2 climbing," Sultan Alam, a Pakistani mountaineering guide, told AFP from the peak's base camp located at an altitude of 5,200 metres.

The exact number of climbers affected remains unclear but Alam said he was aware of 17 whose ropes were swept away, with 11 dead, two stuck on the mountain and three back at Base Camp.

"One Dutch was rescued by helicopter from K2 this morning while an Italian is still at an altitude of 7,200 metres," Alam said as the roar of a helicopter could be heard in the background.

Another chopper went up to help the stranded Italian but could not touch down and returned after a brief contact with the climber, said Alam.

"Our four high altitude porters left a while ago and it is expected that they will bring the Italian climber down this evening," he said.

The avalanche happened when a pillar of ice broke away in a steep gully known as the Bottleneck about 1,300 feet below the summit and swept away fixed lines used by the mountaineers as they made their descent.

"The three mountaineers who survived are suffering from severe frostbite," said Alam, who works for Adventure Tours Pakistan, which operated one of the expeditions caught up in the disaster.

"They are 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," the guide said.

He said that the place where the accident happens was "dangerous" and needed great technical skill to cross.

Citing the climbers, he said that a Spanish climber had just got past the Bottleneck when the avalanche happened.

"The rope collapsed and the climbers started falling in various directions, some fell in (neighbouring) China, some in Pakistan," he said.

The incident was the worst since 1986 when 12 climbers died, said Nazir Sabir, a celebrated Pakistani mountaineer who scaled K2 in 1981.

The pyramid-shaped K2, which sits on the border between Pakistan and China in the towering Karakoram range, is considered by mountaineers to be by far the hardest of the 14 summits over 8,000 metres to scale.

"I have carried down both living and dead people from the mountain," the climber, Fredrik Straeng, told the Swedish news agency TT, explaining how he feared for his life when a Pakistani fell on top of him.

He also put the death toll at 11.

"I was terrified that he 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 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 the mountain 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