Panaji, Oct 28 (IANS): Three Russian women tourists drowned when their boat capsized while on a dolphin-sighting excursion off a beach in Goa, police said Tuesday. The tour operator has been booked for negligence and endangering lives.

A representative of the Russian consular services, however, asked how a boat could be allowed to venture into the sea when a cyclone warning was in place.

The incident took place around mid-day Tuesday off the Betul beach in south Goa, 50 km from Panaji.

A police official said the women were on a dolphin-sighting trip in a motor-powered boat when the vessel capsized after encountering a large wave.

"They were trapped under the boat and drowned because they could not breathe," said a police official engaged in the rescue work.

Dolphin-sighting tours are common along popular Goa beaches where speedboats are used to chase down dolphins swimming in the sea more than a kilometre off the coastline.

The deceased women have not been identified. But post-mortem formalities were being conducted at the Hospicio government hospital in Margao, 35 km from here.

Vikram Varma, a lawyer for the Russian consulate in Mumbai, alleged negligence on the part of the water sports operator who arranged the dolphin sighting trip, as meteorological officials and the state fishing department have directed people not to venture into the sea which was turbulent because of cyclone Nilofar which is passing along the state's coastline.

"When there was a warning issued, how could the boat enter the sea," Varma asked.

Tourism director Ameya Abhyabkar termed the incident "unfortunate".

"The capsized boat was operating without permissions and an FIR has been registered against the boat operator," he said.

Goa attracts three million tourists annually, half a million of which are foreigners. Russians account for the highest number of foreign tourists coming to the state.