The Swiss military has launched a search for a pilot and his plane after a fighter aircraft belonging to the country's air force went missing during a training exercise on Monday.
The plane, a one-seater F/A-18C, disappeared near Susten in central Switzerland on Monday afternoon, the Swiss defense ministry said.
The suspected accident site in the mountainous Alpine region was difficult to access, with bad weather and darkness hampering the search efforts, it added.
Swiss Air Force commander Aldo Schellenberg told a media conference he was deeply shocked by the incident.
When asked about the survival chances of the pilot, he said: "We hope and pray," Swiss news agency SDA reported.
The incident began when the aircraft took off from the air base at Meiringen at 1401 GMT as the second plane in a training exercise.
Radio contact with the base was lost at around 1405 GMT, and the plane was logged as missing.
A search mission was launched with helicopters, but was later abandoned due to bad weather. Two ground-based search teams have also begun looking for the pilot and the aircraft, while an investigation into the suspected crash is now underway.
Family members of the pilot, who has not been named, have been informed and were being cared for by the military.
The incident is the third time the Swiss Air Force has lost one of its F/A 18 jets in the last three years. A pilot was injured when an aircraft crashed in October 2015 in southeast France, while another F/A 18 crashed in 2013.
Earlier this year a Swiss F-5E air demonstration fighter jet collided with another plane and crashed into a pond in the northern Netherlands ahead of an air show.