An Israel Defense Forces officer was killed and another soldier was wounded Tuesday in an accident at an IDF training base in southern Israel.

Capt. Yishai Rosales, of the IDF’s haredi Netzah Yehuda Battalion, was killed when a mortar shell was accidentally fired in his direction. The other soldier sustained minor injuries.

It is unclear why the mortar shell exploded in the vicinity of the soldiers, who were training at the base. Initial details suggest that the incident occurred as a part of a multi-unit training drill for company and battalion commanders.

During the drill, a soldier with the Armored Corps’ 75th Battalion fired an 81 mm mortar shell that exploded right next to Rosales, who was taking part in a different drill nearby. Rosales sustained critical wounds and died shortly afterward. He was posthumously promoted to the rank of captain.

The other soldier wounded in the incident was airlifted to the Soroka Medical Center in Beersheba.

All training at the base has been suspended until the investigation into the accident, headed by a special task force, is complete. Initial assessments suggest the accident was the result of human error. Among other things, the investigation will focus on whether the error was made by the soldier who fired the shell or by the commander who ordered the shooting. The possibility of a technical malfunction will also be investigated.

Tuesday’s tragedy marks the first time in three years that an IDF soldier has been killed during a training exercise. Last May, one reservist was seriously wounded and three others were lightly injured when an armored personnel carrier flipped over during training in the Golan Heights.

Rosales, 23, from Beit Meir, immigrated to Israel from Mexico in 2001 with his parents and brother. Until six months ago, he lived in Kochav Yaakov in the Binyamin region.

The residents of Kochav Yaakov remembered him as a happy, kind-hearted man, who loved to laugh and make others laugh. He donated to the needy anonymously, adopted a lone soldier, and always rushed to help anyone who was in need, they said.

“I remember once he asked me to come with him to build a sukkah for someone who was unable to build one for themselves,” said Ohad, 17, from Kochav Yaakov. “He was like an older brother to me. He loved to watch soccer games and to play [soccer]. He helped me train so that I could play on the town’s team. Whenever he saw someone who was standing on the sidelines while we played he would make sure that someone invited them to play.”