Tokyo, April 7 -- Three people have been confirmed dead after a medical transport helicopter crash off southwestern Japan on Sunday, Kyodo News reported, citing the coast guard.

The coast guard said the death of an 86-year-old female patient, one of six people on board, was confirmed on the day of the incident. A 68-year-old male family member accompanying her and a 34-year-old male doctor were also pronounced dead on Monday.

Local authorities took measures to prevent the helicopter from sinking and monitored it while working to determine the exact cause of the accident. The helicopter left the airport on the island of Tsushima in the Nagasaki Prefecture around 1:30 pm on Sunday.

The helicopter was scheduled to arrive at a hospital in ...