ROME (AP) — An Italian expert joined police divers and rescue vessels for searches in the Maldives on Friday, a day after five Italian divers were killed in a scuba accident, authorities said.

Italy’s Foreign Ministry said the five divers “apparently died while attempting to explore caves at a depth of 50 meters (164 feet)” on Thursday. It said the circumstances of their death remain under investigation.

Maldivian authorities said they launched a major rescue operation after the incident on Thursday, deploying boats, aircraft and dive teams to search the area. One diver was found dead in a deep underwater cave, with the body recovered from nearly 60 meters (200 feet) below the surface, the Maldives National Defense Force said in statement.

The remaining four divers were believed to be inside the same cave, and additional teams and specialized equipment were being sent for what officials described as a dangerous, high-risk operation.

The Italian foreign ministry did not provide information on the recovery of bodies. It said an Italian expert was assisting the coast guard and Maldivian vessels in the search operation on Friday.