The death toll from the eruption of Indonesia’s Mount Marapi volcano has risen to 13 after rescue teams discovered two more bodies on Monday, Report informs via DW.

With 10 climbers still missing and inclement weather impeding rescue efforts, authorities fear that the number is set to rise.

“We don’t expect to find any more survivors,” said Abdul Malik, the head of the local rescue service, which successfully took 49 people off the mountain.

“The safety of our team has to be our priority. It’s been raining incessantly since yesterday evening, making paths slippery and hindering the evacuation team.”

Rescuers are focusing on a particularly popular rocky area where many climbers are thought to have camped, but Malik said conditions were making it almost impossible to deploy search drones.

Mount Marapi on the island of Sumatra — not to be confused with the similarly named volcano Mount Merapi on the island of Java — is 2,891 meters high and one of the most active volcanoes in Indonesia.

Experts had detected signs of increased volcanic activity over the past several months. Marapi erupted on Sunday, spewing an ash tower 3,000 meters high and raining volcanic debris onto nearby villages. Many of the dead showed signs of severe burns.

“Some suffered from burns because it was very hot, and they have been taken to the hospital. Those who are injured were the ones who got closer to the crater,” Rudy Rinaldi, head of the West Sumatra Disaster Mitigation Agency told AFP news agency.

Authorities set up a three-kilometer evacuation zone around the crater and ordered residents to wear face masks, hats and glasses to protect themselves from volcanic ash other debris.

Dozens of smaller eruptions have been detected since the main eruption.