More than 300 illegal immigrants were missing and feared dead off India's eastern coast after they jumped from a rickety boat that had been drifting for 13 days and tried to swim to shore, an official said Monday. Authorities rescued 102 others on the boat.

Authorities were searching for the missing people in the waters near the Andaman Islands, where they were believed to have jumped overboard, said Vijay Singh, an Indian coast guard spokesman.

Roughly 300 people from Bangladesh and Myanmar had tried to swim to the Andaman Islands by the time Indian officials found the boat and its 102 remaining passengers Saturday, he said.

The rescued people were brought to Port Blair, the Andaman capital, Singh said.

The Andamans are a remote chain of Indian-ruled islands some 850 miles off India's east coast. They lie closer to Thailand and Myanmar.

The illegal immigrants said they had been detained by Thai authorities for illegally entering Thai waters before they were sent back out to sea, Singh said.

Police Lieutenant General Chatchawal Suksomjit, commander of Thailand Immigration Office, disputed that claim.

"Thai immigration office will never send illegal immigrants back to their countries by putting them back in the boat then let them go," Chatchawal said. "Normally, when we arrest them, we will send them back through immigration check points along the border."

Poor Bangladeshis often pay up to $300 a head to trafficking syndicates to carry them to Thailand or Malaysia to search for better jobs. They often travel in dangerous boats that have been known to capsize and sink.

The Bangladeshis are sometimes joined by Myanmar refugees, mostly Muslims known as Rohingyas, who have fled Myanmar's military junta for Bangladesh.

Malaysia estimates there are 500,000 to 700,000 illegal immigrants in the country in addition to more than 2 million legal foreign workers, who mostly work in low-paying menial jobs on construction sites and restaurants. But rights groups says there are 5 million undocumented workers in the country.