(BSS/AFP) - The Maldives suspended the operating licence of a luxury vessel on Saturday after five of its Italian passengers perished in the deadliest diving disaster in the Indian Ocean tourist destination.

Rescuers were searching for a third day for the Italians who failed to return after a dive on Thursday, officials said. One body from the group of five was recovered the same day.

The University of Genoa said the victims included a marine biology professor, her daughter and two young researchers.

Chief government spokesman Mohamed Hussain Shareef said an investigation had been launched into why the group went below the officially permitted depth of 30 metres (98 feet).

The body of one diver, yet to be publicly named, was found in a cave at a depth of 60 metres (196 feet).

The first search to locate the other four members of the group was unsuccessful on Friday.

"The Ministry of Tourism and Civil Aviation has suspended the operating licence of the liveaboard vessel MV Duke of York indefinitely, pending the outcome of an investigation into the diving incident that occurred in Vaavu Atoll on May 14," the ministry said.

The Duke of York is a 36-metre luxury boat that can accommodate 25 guests.

Italy`s foreign ministry confirmed on Thursday that all five of its nationals had died.

The low-lying Maldives, a nation of 1,192 tiny coral islands scattered some 800 kilometres (500 miles) across the equator in the Indian Ocean, is a luxury holiday destination popular with divers, who often stay at secluded resorts or on liveaboard dive boats.

Diving and water-sport-