Seven Britons were among 19 people killed when a small plane crashed soon after takeoff from Kathmandu airport, Nepal, possibly after hitting a large bird of prey.
Five other tourists, believed to be from China, also died along with four Nepali passengers and the plane's crew.
The plane, a twin-engined Dornier run by the local Sita Air, crashed on the banks of the Manohara river at 6.18am on Friday morning.
The seven Britons had arrived in Nepal on Wednesday for a trek in the Khumbu Region around Mount Everest.
According to Sherpa Adventure Travel, the Kathmandu-based tour company that organised their trip, they were due to return on 16 October.
No immediate cause was obvious, the deputy police chief at the Tribhuvan international airport (TIA), Superintendent Rabiraj Shrestha said, but hitting a large bird may be one possibility.
The weather was clear.
Shreshtra said rubbish dumped along the sides of the airport attracted large numbers of birds and a dead eagle was recovered from among the wreckage.
"A bird might have been sucked into the engine and caused problems due to which the pilot might have took decision for emergency landing and as a result the plane crashed," he told reporters.
Eyewitnesses say a fire broke out as soon as the plane made an emergency landing on the banks of the Manohara.
The flight's destination was the small airstrip of Lukla, which is the start of many treks in the Everest region.
Late September and October are favoured periods for walking and mountaineering in the Nepali Himalayan ranges as the summer rains have cleared and winter temperatures are yet to bite.
With often hazardous weather conditions and complex terrain, accidents are common. Regulation of the domestic aviation sector in poverty-stricken Nepal is lax. Rubbish beside the runway of a busy airport would normally be considered a significant hazard.
In September 2011, 19 people including 16 tourists were killed when a Buddha Air flight crashed on a similar route.
In August 2010, 14 passengers including four Americans, a Briton and a Japanese nationals were killed after a plane heading to the Everest region crashed due to bad weather.
Similarly, in December 2010, all 22 passengers were killed when another plane came down.
The Foreign Office in London said:"We can confirm that there were British national fatalities. The embassy in Kathmandu remains in contact with the Nepalese authorities."
A spokeswoman added that the ambassador, John Tucknott, had gone to the hospital where the bodies were taken.
The FO would not release any details of the numbers or names of those killed until those had been confirmed and next of kin had been told, she said. Concerned relatives should ring 020 7008 1500.
