At least 13 bodies have been found at a Kazakh border checkpoint on Wednesday where a fire had allegedly broken out, the first deputy director of the Kazakh border service said, according to RIA Novosti.

The incident took place at a mobile border checkpoint in the Alakolsky district of the Almaty Region in southeastern Kazakhstan, which borders on China. The checkpoint only operates in summer to prevent Chinese from collecting local herbs, KazTAG said. Some reports said the men had been murdered.

“At the moment, we have found the burnt remains of 13 people,” Turgenbek Stambekov, first deputy chief of the Kazakh frontier service, told a briefing in the capital, Astana. He added the bodies included one local hunter.

After the border guards failed to contact their bosses as scheduled, their colleagues were summoned to the site on May 30 and found the bodies, KazTAG said.

Police are considering an attack on the border checkpoint or bullying as possible reasons for the incident. Some reports have said the weapons had been stolen from the dead border guards.