Nepal risks a return to "confrontation and conflict" if its leaders fail to agree on a post-war constitution due next week, a senior U.N. official said Wednesday.

The Himalayan nation has endured prolonged political limbo since the end of a decade-long civil war in 2006 as parties have struggled to complete a draft constitution expected to cement the peace process.

An Australian trekker hiking in Nepal's Everest region has died of suspected altitude sickness after falling unconscious, local police and a trekking company official said Tuesday.

The 64-year-old, his niece and their guide were returning from the scenic Gokyo Lakes region, which lies at an altitude of 4,700-5,000 meters (15,420-16,4000 feet), when he fell sick on Sunday evening.

A Nepal court has jailed two men who worked at a prominent orphanage in Kathmandu for repeatedly raping three autistic girls in their care, an official said Tuesday.

A judge at the district court in Kathmandu found the two men guilty of rape on Monday evening in a fast-track case that has cast a spotlight on Nepal's massive orphanage industry.

Police in Kathmandu Wednesday arrested a group of protesters demonstrating near the venue of a regional summit to demand that authorities drop a treason case against a prominent Nepalese activist.

Authorities last month charged Chandra Kant Raut, a former scientist with a doctorate from Britain's Cambridge University, with treason over his calls for a separate homeland for Nepal's marginalised Madhesi community who live in the southern plains. 

Rescuers pulled 44 more bodies from a fast-flowing river in western Nepal where a bus crashed last week, hiking the death toll to 47, police said on Monday.

Emergency workers found three bodies immediately after the crash in mountainous Jajarkot district on Thursday, and pulled another 44 from the wreckage of the bus over the weekend.

At least 24 people were feared dead when a passenger bus plunged Thursday into a river in mountainous western Nepal, triggering a search operation for any survivors, police said.

The bus, carrying at least 45 passengers, veered off a narrow road in Jajarkot region in the morning, police officer Sher Bahadur Chaudhary said.

Two passenger buses collided in central Nepal in the early hours of Saturday, killing at least 10 people, including a Russian woman, police said.

The buses crashed into each other along a national highway in Makwanpur district, 33 kilometers (20 miles) south of Kathmandu, said local police official Prakash Jung Karki.

A German climber has died while descending a Himalayan peak in eastern Nepal, one week after an American fell to his death on the same mountain, police said Wednesday.

The 58-year-old man died on Monday morning while using fixed ropes on his descent after scaling the 6,812-meter (22,349-foot) Ama Dablam mountain in the Everest region, said local police official Khagendra Bahadur Khadka.

An overloaded bus plunged down a hill in central Nepal on Friday, killing at least 14 people including three foreigners, police said.

The bus was crowded with tourists and Nepalese people travelling for the Hindu festival of Tihar when it crashed in Nuwakot, a small hill town outside Kathmandu, local police official Sarita Rajbhandari told Agence France Presse.

Nepal on Wednesday called off a search for any more survivors of a Himalayan snowstorm that claimed some 43 lives, after more than a week of scouring the popular trekking region.

Emergency workers have airlifted 518 people to safety, including 310 foreign tourists, since the snowstorm struck the Annapurna Circuit during peak season, catching trekkers, their guides and porters unawares.