A Maldivian military diver has died during a high-risk operation to recover the bodies of four of the Italian scuba divers who drowned while exploring a deep underwater cave in the Maldives.

The diver suffered underwater decompression sickness after searching for the bodies of the Italians who, according to Italy’s foreign ministry, had “apparently died while attempting to explore caves at a depth of 50 metres (164ft)”.

Mohamed Hussain Shareef, the Maldives presidential spokesperson, said that Mohamed Mahudhee, a member of the Maldivian national defence force, died of the sickness after being transferred to a hospital in the capital, Male.

“The death goes to show the difficulty of the mission,” he said.

Authorities had temporarily suspended attempts to recovery the bodies on Friday, owing to bad weather, but resumed the search on Saturday.

Mahudhee was part of the group of divers who had briefed the Maldives president, Mohamed Muizzu, on the rescue plan when he visited the search site on Friday.

In total, five Italians died in the scuba diving accident in Vaavu Atoll in the Indian Ocean archipelago on Thursday, Italy’s foreign ministry said.

The body of the fifth diver was found near the mouth of a cave shortly afterwards, and rescuers believe the remaining four divers are inside the same cave, which is divided into three large chambers connected by narrow passages.

Working in pairs, a recovery team of eight divers had already explored two of the three chambers on Friday, but were hampered in their efforts to explore the third chamber.

The search resumed on Saturday, with two Italians – a deep-sea rescue expert and a cave diving expert – expected to join the recovery effort.

Italy’s foreign minister, Antonio Tajani, said the Italian government “will do everything possible to recover the bodies of our compatriots”.

The deceased have been identified as Monica Montefalcone, an associate ecology professor at the University of Genoa, her daughter Giorgia Sommacal, marine biologist Federico Gualtieri, researcher Muriel Oddenino and diving instructor Gianluca Benedetti, whose body has been recovered.

The causes of their deaths is unknown and is being investigated.

Officials said the incident was the worst single diving accident in the Maldives, which has 1,192 tiny coral islands scattered across hundreds of miles of the Indian Ocean.

The University of Genoa said Montefalcone and Oddenino were on an official scientific mission to monitor marine environments and study the effects of the climate crisis on tropical biodiversity.

Montefalcone’s husband, Carlo Sommacal, said he believed an incident must have occurred and ruled out recklessness on his wife’s part. “Something must have happened,” he told Italian TV channel Rete 4.

He added that his wife, an experienced diver who had survived the Boxing Day tsunami in 2004 while diving off Kenya, “had two lives – one on land and one in her environment, the water”.

He described her as a disciplined diver who carefully weighed risks before each descent and recalled her telling him at times: “This one I can do, you can’t.”

Diving at 50 metres exceeds the maximum depth recommended for recreational divers by most scuba certifying agencies. Depths beyond 40 metres are considered technical diving, which requires specialised training and equipment. The recreational diving limit in the Maldives is 30 metres (98ft), and experts have warned that cave divers could easily become disoriented or lost, particularly when sediment clouds reduce visibility.

The Italians were passengers onboard a 36-metre luxury yacht the Duke of York, whose operating licence was suspended “indefinitely” on Saturday by the Maldivian ministry of tourism and civil aviation, pending the outcome of an investigation. A website link related to the ship was not working on Saturday and the owner of the yacht did not immediately respond to a request for comment by the Guardian.

Shareef said investigators were looking into why the group went below the officially permitted depth of 30 metres.

Greenpeace Italia, the environmental organisation, paid tribute to Montefalcone as a passionate advocate for marine protection, and said it would miss “her professionalism and her advice immensely”. It recalled the “special light she had in her eyes” when speaking about the wonders of the sea and the importance of protecting them.