PARIS (AP) — French rescue officials said Tuesday they found the bodies of two Italian and two South Korean climbers close to the peak of Mont Blanc on the French side after they went missing over the weekend in bad weather.

The Chamonix-Mont Blanc search and rescue team found the two pairs of climbers at an altitude of 4,700 meters (more than 15,400 feet) on the Alps’ highest peak. They died of hypothermia, rescue officials said.

The unaccompanied climbers had alerted rescuers on Saturday afternoon, but weather conditions continued to deteriorate, preventing rescuers from reaching their location from the ground or by helicopter.

Two other Korean climbers were successfully rescued on Sunday morning at an altitude of 4,100 meters (more than 13,400 feet) after rescuers deployed a highly complex operation.

French authorities have opened an investigation.