A Defence spokesperson said a Naval helicopter, launched by the Southern Naval Command, has rescued four others who were on board the ill-fated vessel Anugraha.
He said the Coast Guard this morning received information about the fishing vessel "taking in water 12 nautical miles NW" off Alappuzha. Upon receiving information, the Southern Naval Command has diverted INS Kalpeni to the area, he said.
A helicopter has also been launched for Search and Rescue, weather permitting, he added.
"There were seven people. Four fishermen have been rescued by Naval ALH helicopter and brought back to INS Garuda in Kochi. Three still missing. Dornier aircraft in the area and searching," the spokesperson said in a communication sent out to media here.
All of them hailing from Vypin, were taken for medical examination in a facility in the Naval base, he added.