Helicopters have begun airlifting foreign tourists from a group of 2,500 stranded by heavy fog in the Everest region, an official said Saturday, but the rescue has been hampered by the poor weather.
Officials were forced to close the only airstrip serving Lukla, the gateway for trekkers and mountaineers heading to Everest and surrounding mountains, on Wednesday, grounding all flights in and out of the region.
Around 120 of the stranded trekkers have so far been ferried back to Kathmandu by privately-owned helicopters from a village 90 minutes' walk away, said Utsab Kharel, the manager of Tenzing Hillary Airport in Lukla.
"The weather situation has further deteriorated in Lukla. The visibility is almost zero and there is no possibility of resumption of regular flights today," he told AFP.
The army had hoped to deploy its rescue helicopter, which carries 30 to 40 people, but bad weather has prevented it from accessing Lukla, 135 kilometres (84 miles) from Kathmandu.
"Small helicopters are only carrying six to seven passengers in a flight," said Kharel.
The stranded trekkers, including Americans, Britons and Germans, have been sleeping at the airport and in tents and dining halls at Lukla hotels, local officials say, with the fog not expected to lift until Sunday.
"We believe that around 2,500 persons are stranded due to the disruption of flights," Kharel said. "We have known that some of the tourists have walked to Kathmandu via Jiri fearing the bad weather would not improve immediately."
Nepal, a popular destination for mountaineers and trekkers, has eight of the world's 14 tallest peaks over 8,000 metres, including the world's highest, Mount Everest, at 8,848 metres (29,029 feet).
Thousands of foreign tourists visit the Everest region during the peak tourism season late in the year.
Around 500 travellers fly in and out of Lukla on a normal day when weather conditions are good.