New Delhi - Indian authorities Monday said they had intensified search operations to find survivors from among 305 men, feared drowned off the Andaman and Nicobar Islands in the Bay of Bengal.

The migrants, Bangladeshi and Burmese nationals, went missing after they jumped from boats and tried to swim ashore on the night of December 26.

Of the total 412 men on the boats, at least 99 were rescued by the Indian Coast Guard and six men were able to swim ashore or were rescued by the police.

Two bodies were found on the shores of the island group, located 1,200 kilometres off the Indian mainland.

"305 men are still missing, going by the total figure of 412 given by the survivors," Ranjit Narayan, police chief of the Andamans and Nicobar Islands said over phone.

Narayan said although search operations were intensified in the region, no survivors could be traced on Monday.

"The Coast Guard, the Navy, Army and local police are all involved in the search operations and ships, helicopters as well as aircraft have been pressed into service," Narayan said adding that the search operations will continue as there could be some survivors.

Coast Guard officials, citing survivors, said the migrants had left some 45 days earlier from Bangladesh for Thailand and Malaysia, where they planned to work.

Survivors said the 412 men, mostly Bangladeshis and some Burmese were on six boats which were spotted by the Thai Navy after they reached Thai waters.

The migrants were detained for about four weeks and later put on non-mechanized boats with some bags of rice in the high seas to reach home, survivors told Indian officials.

They were drifting in the Bay of Bengal for 12 days before they reached the vicinity of the island group. On Friday night one of the men swam to Hut Bay and told the authorities that many others were drifting on the sea.

In subsequent operations over the weekend, 88 people were found on a boat near the Little Andaman Islands, located 80 kilometres south of state capital Port Blair. Another 11 men were rescued from the sea and an adjoining island.

"Survivors have said many of those on the boats, numbering over 300, had jumped into the sea hoping to swim ashore," said Indian Coast Guard spokesman Commandant Vijay Kumar.

Kumar said the survivors were in poor health as they had little food or water during the past few weeks. Police and intelligence officials were questioning the men to verify their statements.

"The survivors were provided first aid and medical treatment. Many of them them are being questioned to find the details of the illegal trafficking," Kumar said. (dpa)