KATHMANDU, Nepal (AP) — An American and a Swiss climber have died on Mount Everest in the season's first casualties on the world’s highest mountain.

Expedition organizers say the Swiss climber reached the peak but had difficulties on the way down and died.

The U.S. climber had to be helped down to the highest camp before he reached the summit. He died at the camp.

Their bodies are to be brought down after weather conditions improve.

Scores of climbers reached the summit this week while weather conditions were favorable, and more are expected to attempt the climb later this month.