ISLAMABAD: Three climbers have gone missing attempting to summit the world's second-highest mountain, K2, their expedition manager and the Alpine Club of Pakistan said Saturday.

Climbers John Snorri from Iceland, Juan Pablo Mohr from Chile and Muhammad Ali Sadpara from Pakistan reportedly lost contact with base camp on Friday.

"It's already been more than 30 hours, we (at basecamp) have received no news of John Snorri, Ali Sadpara, and Juan Pablo Mohr, since none of the GPS trackers seem to be working", Chhang Dawa Sherpa, their expedition manager, said in a statement.

An army helicopter has conducted a search flight for the missing climbers, Sherpa said in a separate statement.

"Unfortunately, they cannot trace anything and the condition up in the mountain and even at the basecamp is getting poor", he said.

Karrar Haidri, Secretary of the Alpine Club of Pakistan, also told AFP that the climbers had gone missing on the mountain.

News of the missing men comes a day after a Bulgarian mountaineer was confirmed to have died on K2.

He is the third mountaineer to die on K2's slopes this year, after a Spanish climber fell to his death last month.

Russian-American Alex Goldfarb also died on a nearby mountain during an acclimatising mission in January.

A team of Nepali climbers made history on K2 last month when they became the first to scale it in winter.

Conditions on K2 are harsh: winds can blow at more than 200 kilometres per hour (125 miles per hour) and temperatures can drop to minus 60 degrees Celsius (minus 76 Fahrenheit).

With Pakistan's borders open and few other places to go, this winter an unprecedented four teams totalling around 60 climbers have converged on the mountain, more than all previous expeditions put together.

Unlike Mount Everest, which has been scaled by thousands of climbers young and old, K2 is much less travelled due to its tough conditions.