Two American soldiers taking a break from a joint military exercise went missing in Morocco Saturday night.

The two were noted as missing after a headcount during the annual multinational event called “African Lion.” It is presumed that they fell off a cliff into the sea, and a U.S. official said that the incident was not related to the military exercise.

“They were not actively taking part in any training. The day’s exercises had concluded, and, from our understanding, they were out on a recreational hike,” the official told the Associated Press, speaking anonymously, as he had not been granted permission to speak publicly about the disappearance.

The United States Africa Command said in a statement that the U.S., Morocco and other countries joined in the rescue mission, which included the use of helicopters, mountain rescue units, divers and ships, according to the AP.

“The incident remains under investigation and the search is ongoing,” it said.

The military encampment was set up on desert and semi-desert areas, a short walk away from where the sand met the ocean.