KATHMANDU-Authorities in Nepal have been unable to confirm the identities of four bodies found on Mount Everest, officials said Wednesday, raising speculation the climbers may have died years ago.

The climbers were found at camp four - at 7,950 metres (26,085 feet) - on Tuesday by a rescue team who were there to retrieve the body of a Slovak climber who died on the mountain on Sunday.

“Our rescuers found bodies of four climbers in a tent at camp four yesterday. We don’t have the details of who they are or how they died yet,” said Mingma Sherpa, head of Seven Summit Treks, a Kathmandu-based agency that runs expeditions and rescue operations on the mountain.

Local media reported that two of the dead were foreign climbers and two were Nepali guides. Nepal’s tourism department said late Wednesday they had been unable to identify the bodies.

“Our sources at the base camp were not able to confirm if any teams were missing members. We suspect that maybe they found bodies from years before,” department spokesman Durga Dutta Dhakal told AFP. Tashi Sherpa, also of Seven Summit Treks, later told AFP that some of the bodies were found inside a tent, while others were discovered outside. Strong winds hit Everest on Tuesday, forcing many to abandon their summit attempts and remain in tents at camp four. This fuelled speculation that the four climbers discovered Tuesday may have died of carbon monoxide poisoning after using their camp stoves in the confines of their tents. If the bodies are confirmed as new fatalities, it would bring the season’s death toll to 10.

Four people perished on the 8,848-metre peak over the weekend, including American doctor Roland Yearwood and Slovak climber Vladimir Strba. Both died above the 8,000 metre mark - an area known as the mountain’s “death zone” where oxygen levels fall to dangerously low levels, heightening the risk of altitude sickness.

The body of Indian climber Ravi Kumar, 27, was spotted on Monday two days after he summited and then lost contact. An Australian climber died on the Tibet side of the mountain on Sunday.

This season has also claimed the lives of legendary Swiss climber Ueli Steck and 85-year-old Min Bahadur Sherchan, who died attempting to reclaim his title as the world’s oldest person to climb Everest.

More than 382 climbers, both foreign and Nepali, have successfully reached the summit from the south side so far this season, with at least 120 doing so from the Tibet side.